Pianotech

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Have you tried a thread restorer?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Have you tried a thread restorer?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

Have you tried a thread restorer?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

Have you tried a thread restorer?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

The part is in the Steinway Parts Photo Addendum p.17

The 2014 price list is a little cryptic*. 

*009060 LEG & LYRE PLATE LOCKS (M & F) - NEW STYLE (USE W/ #097873)

It might be informative to remove the assembly from the leg. Those loose threads at the bottom of your picture may be from the lock itself. I'm not sure if they'd thread both parts, seems like a recipe for disaster. You might want to compare to one of the functional legs too.

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 21:18
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 12-27-2024 11:27
From: David Love
Subject: Hamburg Steinway Leg Repair

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 22:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Have you tried a thread restorer?

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Oh, I see, the #097873 is the hex key.

097873 LEG/LYRE PLATE LOCK - HEX KEY (USE W/ #009060) (8 mm or 5/16" Allen key )

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 22:23
From: Steven Rosenthal
Subject: Hamburg Steinway Leg Repair

The part is in the Steinway Parts Photo Addendum p.17

The 2014 price list is a little cryptic*. 

*009060 LEG & LYRE PLATE LOCKS (M & F) - NEW STYLE (USE W/ #097873)

It might be informative to remove the assembly from the leg. Those loose threads at the bottom of your picture may be from the lock itself. I'm not sure if they'd thread both parts, seems like a recipe for disaster. You might want to compare to one of the functional legs too.

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 21:18
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 12-27-2024 11:27
From: David Love
Subject: Hamburg Steinway Leg Repair

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 22:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Have you tried a thread restorer?

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

So, from this it appears what you have is destroyed threads in the unit itself. I would not be surprised if you couldn't simply cut new threads and get a bigger hex bolt, but if you want to just buy the part, why not?

Seems to me likely that if one has been stressed beyond it's limit, the other two might be suspects for early failure as well. 

Peter Grey Piano Doctor 

Oh, I see, the #097873 is the hex key.

097873 LEG/LYRE PLATE LOCK - HEX KEY (USE W/ #009060) (8 mm or 5/16" Allen key )

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 22:23
From: Steven Rosenthal
Subject: Hamburg Steinway Leg Repair

The part is in the Steinway Parts Photo Addendum p.17

The 2014 price list is a little cryptic*. 

*009060 LEG & LYRE PLATE LOCKS (M & F) - NEW STYLE (USE W/ #097873)

It might be informative to remove the assembly from the leg. Those loose threads at the bottom of your picture may be from the lock itself. I'm not sure if they'd thread both parts, seems like a recipe for disaster. You might want to compare to one of the functional legs too.

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 21:18
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 12-27-2024 11:27
From: David Love
Subject: Hamburg Steinway Leg Repair

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 22:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Have you tried a thread restorer?

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

What Peter said. However, the problem could have been caused by a replacement bolt that was the wrong size or was just over tightened. 

At least they've gone from cast iron to steel. Probably more durable in the long run. It looks like the bolt threads through the outer ring and presses the inner -male part- into a (T?) slot to lock it in.

So, from this it appears what you have is destroyed threads in the unit itself. I would not be surprised if you couldn't simply cut new threads and get a bigger hex bolt, but if you want to just buy the part, why not?

Seems to me likely that if one has been stressed beyond it's limit, the other two might be suspects for early failure as well. 

Peter Grey Piano Doctor 

Oh, I see, the #097873 is the hex key.

097873 LEG/LYRE PLATE LOCK - HEX KEY (USE W/ #009060) (8 mm or 5/16" Allen key )

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 22:23
From: Steven Rosenthal
Subject: Hamburg Steinway Leg Repair

The part is in the Steinway Parts Photo Addendum p.17

The 2014 price list is a little cryptic*. 

*009060 LEG & LYRE PLATE LOCKS (M & F) - NEW STYLE (USE W/ #097873)

It might be informative to remove the assembly from the leg. Those loose threads at the bottom of your picture may be from the lock itself. I'm not sure if they'd thread both parts, seems like a recipe for disaster. You might want to compare to one of the functional legs too.

------------------------------
Steven Rosenthal RPT
Honolulu HI
(808) 521-7129

Original Message:
Sent: 12-27-2024 21:18
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 12-27-2024 11:27
From: David Love
Subject: Hamburg Steinway Leg Repair

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 22:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Have you tried a thread restorer?

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

The part is in the Steinway Parts Photo Addendum p.17

The 2014 price list is a little cryptic*. 

*009060 LEG & LYRE PLATE LOCKS (M & F) - NEW STYLE (USE W/ #097873)

It might be informative to remove the assembly from the leg. Those loose threads at the bottom of your picture may be from the lock itself. I'm not sure if they'd thread both parts, seems like a recipe for disaster. You might want to compare to one of the functional legs too.

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

Have you tried a thread restorer?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

That's great, I did not see that in the catalogue. Thanks. I'll make further inquiries. 

The part is in the Steinway Parts Photo Addendum p.17

The 2014 price list is a little cryptic*. 

*009060 LEG & LYRE PLATE LOCKS (M & F) - NEW STYLE (USE W/ #097873)

It might be informative to remove the assembly from the leg. Those loose threads at the bottom of your picture may be from the lock itself. I'm not sure if they'd thread both parts, seems like a recipe for disaster. You might want to compare to one of the functional legs too.

I would guess (repeat...guess) that it's both threaded and with some adhesive used. That said, if I were faced with this I would attempt the use of an EZ-Out after first applying some heat to the general area (obviously not enough to damage anything, but enough to make it HOT, primarily the metal insert to weaken any glue bond that might be there, but secondarily to slightly think the wood around it).

If that ultimately did not work I would then likely drill it out to a point where I could finally remove fragments (hopefully) without destroying existing threads, but if necessary...a larger threaded insert can almost always be found to replace it. 

Peter Grey Piano Doctor 

Yes there is a threaded insert so there are two questions: how it's mounted in there, glued in or threaded in; and getting the replacements.  I have messages in to both NY and Hamburg Steinway on the parts. So mainly I'm wondering who has had to remove that insert and install a new one and what's involved.  

Have you tried a thread restorer?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Should I/we be worried about the safety issue associated with this listserver thread on Steinway Leg Repair?

Steinway has shifted from an iron apron design tested for over 125 years with its internal apron + external wooden chock to a new design using a combined internal metal apron + metal chock. Piano movers, once they see how the new design works, will likely use a power tool (possibly set for too high a torque!) when reattaching the legs after a move. Hence possible odds that the new metal internal chock will have its threads stripped after a move and (for whatever reason) it is possible that no one will know.

Among the Steinway grands I tune or have tuned I have never come across a failure of the old traditional internal iron apron + external wood chock system. I would appreciate hearing from those who have had issues with the old design, as this might help me to understand the reasoning for the recent change. We know from David that an issue has already been observed with the new design.

BTW, 8mm is larger than 5/16", so I would suggest going with an 8mm wrench for use with the new locking screw. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-23-2025 00:33
From: David Love
Subject: Hamburg Steinway Leg Repair

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Norman,

The old interlocking plates needed an outboard locking system to secure the legs in place. Many times, the cast iron interlocking plates would wear out after repeated removal and remounting, particular with rental performance pianos. I'm sure many of us has encountered wedges or "T" cams (the name escapes me) that need additional shims to insure a tight fit.

Should I/we be worried about the safety issue associated with this listserver thread on Steinway Leg Repair?

Steinway has shifted from an iron apron design tested for over 125 years with its internal apron + external wooden chock to a new design using a combined internal metal apron + metal chock. Piano movers, once they see how the new design works, will likely use a power tool (possibly set for too high a torque!) when reattaching the legs after a move. Hence possible odds that the new metal internal chock will have its threads stripped after a move and (for whatever reason) it is possible that no one will know.

Among the Steinway grands I tune or have tuned I have never come across a failure of the old traditional internal iron apron + external wood chock system. I would appreciate hearing from those who have had issues with the old design, as this might help me to understand the reasoning for the recent change. We know from David that an issue has already been observed with the new design.

BTW, 8mm is larger than 5/16", so I would suggest going with an 8mm wrench for use with the new locking screw. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-23-2025 00:33
From: David Love
Subject: Hamburg Steinway Leg Repair

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Should I/we be worried about the safety issue associated with this listserver thread on Steinway Leg Repair?

Steinway has shifted from an iron apron design tested for over 125 years with its internal apron + external wooden chock to a new design using a combined internal metal apron + metal chock. Piano movers, once they see how the new design works, will likely use a power tool (possibly set for too high a torque!) when reattaching the legs after a move. Hence possible odds that the new metal internal chock will have its threads stripped after a move and (for whatever reason) it is possible that no one will know.

Among the Steinway grands I tune or have tuned I have never come across a failure of the old traditional internal iron apron + external wood chock system. I would appreciate hearing from those who have had issues with the old design, as this might help me to understand the reasoning for the recent change. We know from David that an issue has already been observed with the new design.

BTW, 8mm is larger than 5/16", so I would suggest going with an 8mm wrench for use with the new locking screw. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321
------------------------------

Original Message:
Sent: 01-23-2025 00:33
From: David Love
Subject: Hamburg Steinway Leg Repair

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Should I/we be worried about the safety issue associated with this listserver thread on Steinway Leg Repair?

Steinway has shifted from an iron apron design tested for over 125 years with its internal apron + external wooden chock to a new design using a combined internal metal apron + metal chock. Piano movers, once they see how the new design works, will likely use a power tool (possibly set for too high a torque!) when reattaching the legs after a move. Hence possible odds that the new metal internal chock will have its threads stripped after a move and (for whatever reason) it is possible that no one will know.

Among the Steinway grands I tune or have tuned I have never come across a failure of the old traditional internal iron apron + external wood chock system. I would appreciate hearing from those who have had issues with the old design, as this might help me to understand the reasoning for the recent change. We know from David that an issue has already been observed with the new design.

BTW, 8mm is larger than 5/16", so I would suggest going with an 8mm wrench for use with the new locking screw. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-23-2025 00:33
From: David Love
Subject: Hamburg Steinway Leg Repair

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

All - thanks for the info / clarifications. I figured that the old apron design probably has its share of issues. I tend to be a worrier(!), but for an engineer maybe that is OK?

I think that the new Steinway leg design needs careful attention by us when servicing newer Steinway grands; make sure you have an 8 mm Allen wrench in your case. In my personal opinion, this is a major safety issue. Is there Steinway maintenance guidance available that explains how we can validate a proper re-installation after a move?

David has shown how easily a problem with the leg attachment mechanism can occur upon a move, but I would appreciate a description of how one discovers the problem. The old apron design with its external wooden chock has visual indications that will often give us a warning, like the chock not going into place properly (such as a big gap when fully closed or too small a gap hence not significantly closing) – but yes, if the leg/frame numbers are not properly matched after a move you might have a situation where the parts still fit together "adequately".

But for the new design I don't know what visual signs to expect should there be a problem. Might a leg with the metal locking apron not engaged look the same as for one properly installed and tightened? The over-torquing that David found is certainly not to be ruled out. Unfortunately, we have all probably followed up after a piano move with issues with the lyre or the legs not being reassembled correctly (for whatever reason). As I indicated, I would appreciate some guidance from Steinway on this important safety topic.

A related engineering matter is the 90-degree torque that casters exert on a piano leg. For the older, small traditional casters the right-angle offset from dead center was perhaps ¾". I haven't measured the newer casters, but they look like their right-angle offset is at least 2 or 3 inches (anyone have one handy to measure?). This gives a much more significant continual twisting torque to the piano leg. The actual horizontal-plane angle to the twist will randomly depend on the angle of the caster position on the floor, and I wonder if a loose apron fit at the top of the leg could jeopardize structural stability. Regards, Norman.

Should I/we be worried about the safety issue associated with this listserver thread on Steinway Leg Repair?

Steinway has shifted from an iron apron design tested for over 125 years with its internal apron + external wooden chock to a new design using a combined internal metal apron + metal chock. Piano movers, once they see how the new design works, will likely use a power tool (possibly set for too high a torque!) when reattaching the legs after a move. Hence possible odds that the new metal internal chock will have its threads stripped after a move and (for whatever reason) it is possible that no one will know.

Among the Steinway grands I tune or have tuned I have never come across a failure of the old traditional internal iron apron + external wood chock system. I would appreciate hearing from those who have had issues with the old design, as this might help me to understand the reasoning for the recent change. We know from David that an issue has already been observed with the new design.

BTW, 8mm is larger than 5/16", so I would suggest going with an 8mm wrench for use with the new locking screw. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-23-2025 00:33
From: David Love
Subject: Hamburg Steinway Leg Repair

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

All - thanks for the info / clarifications. I figured that the old apron design probably has its share of issues. I tend to be a worrier(!), but for an engineer maybe that is OK?

I think that the new Steinway leg design needs careful attention by us when servicing newer Steinway grands; make sure you have an 8 mm Allen wrench in your case. In my personal opinion, this is a major safety issue. Is there Steinway maintenance guidance available that explains how we can validate a proper re-installation after a move?

David has shown how easily a problem with the leg attachment mechanism can occur upon a move, but I would appreciate a description of how one discovers the problem. The old apron design with its external wooden chock has visual indications that will often give us a warning, like the chock not going into place properly (such as a big gap when fully closed or too small a gap hence not significantly closing) – but yes, if the leg/frame numbers are not properly matched after a move you might have a situation where the parts still fit together "adequately".

But for the new design I don't know what visual signs to expect should there be a problem. Might a leg with the metal locking apron not engaged look the same as for one properly installed and tightened? The over-torquing that David found is certainly not to be ruled out. Unfortunately, we have all probably followed up after a piano move with issues with the lyre or the legs not being reassembled correctly (for whatever reason). As I indicated, I would appreciate some guidance from Steinway on this important safety topic.

A related engineering matter is the 90-degree torque that casters exert on a piano leg. For the older, small traditional casters the right-angle offset from dead center was perhaps ¾". I haven't measured the newer casters, but they look like their right-angle offset is at least 2 or 3 inches (anyone have one handy to measure?). This gives a much more significant continual twisting torque to the piano leg. The actual horizontal-plane angle to the twist will randomly depend on the angle of the caster position on the floor, and I wonder if a loose apron fit at the top of the leg could jeopardize structural stability. Regards, Norman.

Should I/we be worried about the safety issue associated with this listserver thread on Steinway Leg Repair?

Steinway has shifted from an iron apron design tested for over 125 years with its internal apron + external wooden chock to a new design using a combined internal metal apron + metal chock. Piano movers, once they see how the new design works, will likely use a power tool (possibly set for too high a torque!) when reattaching the legs after a move. Hence possible odds that the new metal internal chock will have its threads stripped after a move and (for whatever reason) it is possible that no one will know.

Among the Steinway grands I tune or have tuned I have never come across a failure of the old traditional internal iron apron + external wood chock system. I would appreciate hearing from those who have had issues with the old design, as this might help me to understand the reasoning for the recent change. We know from David that an issue has already been observed with the new design.

BTW, 8mm is larger than 5/16", so I would suggest going with an 8mm wrench for use with the new locking screw. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-23-2025 00:33
From: David Love
Subject: Hamburg Steinway Leg Repair

Follow up on this.  Much easier than I anticipated.  On the Hamburg the old plates come out quite easily and the new ones just drop into place.  Replaced the locking plate on the case as well. Reused the set screws which fit the newly designed part.  Apparently, NY Steinway is going to this configuration, much better than the old system.  Thanks to Peter in Parts and Ben Gac.  Much ado about nothing as it turns out.  Whole operation took about 30 minutes, replaced the lyre plates while I was at it. Be careful not to overtighten the set screw or instruct movers not to use an electric driver.  You can damage the parts though the new one is supposedly a bit more resistant to that.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Les,

I assume Grade 8 equates to "strong"...?

Peter Grey Piano Doctor 

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Les,

I assume Grade 8 equates to "strong"...?

Peter Grey Piano Doctor 

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

Perhaps movers need to have liability insurance at least equal to the value of the piano.

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

For a related discussion, see the thread on this listserver from November 26, 2024, by H. Russell Schmidt that was titled: "Concert Grand Legs Falling Off!".

Excerpting from his post: ". . . . . within the past year, I have had three different incidences in which a leg on a concert grand has folded under the piano or nearly fallen off when being moved. All three instruments where not on spider dollies but have the extra large double wheel brass casters. In two of the incidents, the scews of the leg plate that is in the uderside of the piano loosed up enough to create some play in the leg. This is what contributed to it buckling when going over a theashold or in one case a dampchasser extension chord. . . . ".

David, could the loosened screws that Russell has been observing be the same stripped screws that you observed, or do you think that you and Russell are seeing different failure mechanisms for the same Steinway part?

And does anyone know if Steinway is conducting a reevaluation for its new leg attachment part, perhaps with a plan to include a recall? Just curious. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 14:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Perhaps movers need to have liability insurance at least equal to the value of the piano.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 01-26-2025 13:31
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 01-26-2025 12:27
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Hi Norman,

The post from H. Russell Schmidt did not mention a manufacturer, or an approximate age of the piano in question, but it sounded like the problem in that thread was distinctly different from what David reported.  More on that below, but first let's talk about the leg plates themselves.

The damage to the plates David Love encountered seems to have been a result of mishandling. The screw that is designed to hold the assembly together is a 12.9 grade bolt threaded into a plate with a torque limit of 20nm (approximately 15 foot pounds.)

The problem here arises when a piano mover uses an impact screw driver (often capable of 100 foot pounds or more) to tighten these screws. The 75,000 psi shear strength of the bolt will chew the threads of the plate if excess torque is applied (in this case more than 6 times the necessary force).  The one and only correct fix here is a complete replacement of the plate which David Love has done.

As for the concert casters, The 2.5" offset concert caster on a Steinway model D weighing 990 lbs applies a stationary torque to the leg of approximately 825 inch pounds per leg.  The force the piano leg encounters when it hits a bump like an extension cord can exceed 13,000 inch pounds (or higher depending on the speed). 

Put into perspective, this makes the 825 additional inch pounds from the concert caster somewhat negligible, and the real danger is encountering the bump and the speed at which the bump is encountered.  It would be my bet that the failure H. Russell Schmidt encountered as a result of the piano rolling over a dampp chaser cord was with the wood parts and not the screws or plate, but without being certain of the piano's construction, I can only guess.

Finally, the coming change in the leg plate is part of the unification efforts between both factories, and not because the current New York leg plate which has been in use at the Steinway New York Factory since 2007 has anything inherently wrong with the design. 

If you encounter these leg or lyre plates in the field, simply use an 8mm or 5/16" Allen wrench and hand-tighten until the screw is snug.

------------------------------
Daniel DeBiasio
Technical Education & Support
ddebiasio@steinway.com
718-267-3229
Steinway & Sons

Original Message:
Sent: 01-26-2025 15:51
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

For a related discussion, see the thread on this listserver from November 26, 2024, by H. Russell Schmidt that was titled: "Concert Grand Legs Falling Off!".

Excerpting from his post: ". . . . . within the past year, I have had three different incidences in which a leg on a concert grand has folded under the piano or nearly fallen off when being moved. All three instruments where not on spider dollies but have the extra large double wheel brass casters. In two of the incidents, the scews of the leg plate that is in the uderside of the piano loosed up enough to create some play in the leg. This is what contributed to it buckling when going over a theashold or in one case a dampchasser extension chord. . . . ".

David, could the loosened screws that Russell has been observing be the same stripped screws that you observed, or do you think that you and Russell are seeing different failure mechanisms for the same Steinway part?

And does anyone know if Steinway is conducting a reevaluation for its new leg attachment part, perhaps with a plan to include a recall? Just curious. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 14:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Perhaps movers need to have liability insurance at least equal to the value of the piano.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 01-26-2025 13:31
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 01-26-2025 12:27
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Daniel

I think if you could post a picture from top and sides of the new fitting it would explain a lot.  I've attached a one dimensional image here.  The set screw, part of the leg plate, moves a locking plate (pictured in red) in to secure the two parts together by sliding that plate across that square open area. The set screw does not actually hold the leg.  The sliding lock plate does.

The lock plate (#9060) which attaches to the piano has an extension which is shaped like the lower image, called a frustrum (an inverted pyramid with the smaller end cut off).  When the leg plate is inserted over that as the two parts are assembled, then the set screw moves the metal plate laterally to secure against the narrower base of the frustrum.  Thus, in order for that leg to come apart, not only do you have to loosen the set screw, but you have to loosen it to the point where it no longer impedes the two parts from being separated.  The frustrum shape prevents that separation until the sliding locking plate, actuated by the set screw, is completely withdrawn.  The weakest point of the assembly would probably be the base of the frustrum where it is the narrowest and which is where the sliding lock plate secures against.  I'm sure this is engineered to withstand that sheer stress and not even sure that would be the point of stress, an engineer would have to answer that question.  Again, I'm not worried about leg failure.  Good system, in my view, and an improvement.    

Hopefully that helps.

Hi Norman,

The post from H. Russell Schmidt did not mention a manufacturer, or an approximate age of the piano in question, but it sounded like the problem in that thread was distinctly different from what David reported.  More on that below, but first let's talk about the leg plates themselves.

The damage to the plates David Love encountered seems to have been a result of mishandling. The screw that is designed to hold the assembly together is a 12.9 grade bolt threaded into a plate with a torque limit of 20nm (approximately 15 foot pounds.)

The problem here arises when a piano mover uses an impact screw driver (often capable of 100 foot pounds or more) to tighten these screws. The 75,000 psi shear strength of the bolt will chew the threads of the plate if excess torque is applied (in this case more than 6 times the necessary force).  The one and only correct fix here is a complete replacement of the plate which David Love has done.

As for the concert casters, The 2.5" offset concert caster on a Steinway model D weighing 990 lbs applies a stationary torque to the leg of approximately 825 inch pounds per leg.  The force the piano leg encounters when it hits a bump like an extension cord can exceed 13,000 inch pounds (or higher depending on the speed). 

Put into perspective, this makes the 825 additional inch pounds from the concert caster somewhat negligible, and the real danger is encountering the bump and the speed at which the bump is encountered.  It would be my bet that the failure H. Russell Schmidt encountered as a result of the piano rolling over a dampp chaser cord was with the wood parts and not the screws or plate, but without being certain of the piano's construction, I can only guess.

Finally, the coming change in the leg plate is part of the unification efforts between both factories, and not because the current New York leg plate which has been in use at the Steinway New York Factory since 2007 has anything inherently wrong with the design. 

If you encounter these leg or lyre plates in the field, simply use an 8mm or 5/16" Allen wrench and hand-tighten until the screw is snug.

------------------------------
Daniel DeBiasio
Technical Education & Support
ddebiasio@steinway.com
718-267-3229
Steinway & Sons

Original Message:
Sent: 01-26-2025 15:51
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

For a related discussion, see the thread on this listserver from November 26, 2024, by H. Russell Schmidt that was titled: "Concert Grand Legs Falling Off!".

Excerpting from his post: ". . . . . within the past year, I have had three different incidences in which a leg on a concert grand has folded under the piano or nearly fallen off when being moved. All three instruments where not on spider dollies but have the extra large double wheel brass casters. In two of the incidents, the scews of the leg plate that is in the uderside of the piano loosed up enough to create some play in the leg. This is what contributed to it buckling when going over a theashold or in one case a dampchasser extension chord. . . . ".

David, could the loosened screws that Russell has been observing be the same stripped screws that you observed, or do you think that you and Russell are seeing different failure mechanisms for the same Steinway part?

And does anyone know if Steinway is conducting a reevaluation for its new leg attachment part, perhaps with a plan to include a recall? Just curious. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 14:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Perhaps movers need to have liability insurance at least equal to the value of the piano.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 01-26-2025 13:31
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 01-26-2025 12:27
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Below are two parts of the "HH Lyre Lock Plate" in use on the Steinway New York Lyre since 2024.  The Female Lyre Lock Plate (#009059HH) and the Male Lyre Lock Plate (#009058HH) are shown below in both the open and closed position. This lock plate has been in use by Steinway Hamburg for both legs and lyre

Daniel

I think if you could post a picture from top and sides of the new fitting it would explain a lot.  I've attached a one dimensional image here.  The set screw, part of the leg plate, moves a locking plate (pictured in red) in to secure the two parts together by sliding that plate across that square open area. The set screw does not actually hold the leg.  The sliding lock plate does.

The lock plate (#9060) which attaches to the piano has an extension which is shaped like the lower image, called a frustrum (an inverted pyramid with the smaller end cut off).  When the leg plate is inserted over that as the two parts are assembled, then the set screw moves the metal plate laterally to secure against the narrower base of the frustrum.  Thus, in order for that leg to come apart, not only do you have to loosen the set screw, but you have to loosen it to the point where it no longer impedes the two parts from being separated.  The frustrum shape prevents that separation until the sliding locking plate, actuated by the set screw, is completely withdrawn.  The weakest point of the assembly would probably be the base of the frustrum where it is the narrowest and which is where the sliding lock plate secures against.  I'm sure this is engineered to withstand that sheer stress and not even sure that would be the point of stress, an engineer would have to answer that question.  Again, I'm not worried about leg failure.  Good system, in my view, and an improvement.    

Hopefully that helps.

Hi Norman,

The post from H. Russell Schmidt did not mention a manufacturer, or an approximate age of the piano in question, but it sounded like the problem in that thread was distinctly different from what David reported.  More on that below, but first let's talk about the leg plates themselves.

The damage to the plates David Love encountered seems to have been a result of mishandling. The screw that is designed to hold the assembly together is a 12.9 grade bolt threaded into a plate with a torque limit of 20nm (approximately 15 foot pounds.)

The problem here arises when a piano mover uses an impact screw driver (often capable of 100 foot pounds or more) to tighten these screws. The 75,000 psi shear strength of the bolt will chew the threads of the plate if excess torque is applied (in this case more than 6 times the necessary force).  The one and only correct fix here is a complete replacement of the plate which David Love has done.

As for the concert casters, The 2.5" offset concert caster on a Steinway model D weighing 990 lbs applies a stationary torque to the leg of approximately 825 inch pounds per leg.  The force the piano leg encounters when it hits a bump like an extension cord can exceed 13,000 inch pounds (or higher depending on the speed). 

Put into perspective, this makes the 825 additional inch pounds from the concert caster somewhat negligible, and the real danger is encountering the bump and the speed at which the bump is encountered.  It would be my bet that the failure H. Russell Schmidt encountered as a result of the piano rolling over a dampp chaser cord was with the wood parts and not the screws or plate, but without being certain of the piano's construction, I can only guess.

Finally, the coming change in the leg plate is part of the unification efforts between both factories, and not because the current New York leg plate which has been in use at the Steinway New York Factory since 2007 has anything inherently wrong with the design. 

If you encounter these leg or lyre plates in the field, simply use an 8mm or 5/16" Allen wrench and hand-tighten until the screw is snug.

------------------------------
Daniel DeBiasio
Technical Education & Support
ddebiasio@steinway.com
718-267-3229
Steinway & Sons

Original Message:
Sent: 01-26-2025 15:51
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

For a related discussion, see the thread on this listserver from November 26, 2024, by H. Russell Schmidt that was titled: "Concert Grand Legs Falling Off!".

Excerpting from his post: ". . . . . within the past year, I have had three different incidences in which a leg on a concert grand has folded under the piano or nearly fallen off when being moved. All three instruments where not on spider dollies but have the extra large double wheel brass casters. In two of the incidents, the scews of the leg plate that is in the uderside of the piano loosed up enough to create some play in the leg. This is what contributed to it buckling when going over a theashold or in one case a dampchasser extension chord. . . . ".

David, could the loosened screws that Russell has been observing be the same stripped screws that you observed, or do you think that you and Russell are seeing different failure mechanisms for the same Steinway part?

And does anyone know if Steinway is conducting a reevaluation for its new leg attachment part, perhaps with a plan to include a recall? Just curious. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 14:28
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

Perhaps movers need to have liability insurance at least equal to the value of the piano.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 01-26-2025 13:31
From: Peter Grey
Subject: Hamburg Steinway Leg Repair

A lot of time these kind of changes are instigated by the legal dept, wanting to reduce or eliminate a system that is "theoretically" prone to failure that could result in liability. 

My question is, does each piano come with the appropriate hex wrench such that it can be used as needed to tighten a slightly loose leg or lyre? Or are we expected to carry these things? (Which I do...)

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com

Original Message:
Sent: 01-26-2025 12:27
From: Norman Brickman
Subject: Hamburg Steinway Leg Repair

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Rather than us idly speculating on design failure possibilities, I suggest talk to Steinway if you have concerns. They recently reengineered these plates (I'm told!). The bolts don't appear to take much, if any, of the load or stress from moving the piano. They simply move the locking mechanism in place. It takes several turns of the bolt to tighten the mechanism such that any failure from the bolt coming loose seems very unlikely. I suppose it's possible that someone could finger tighten them and not use an Allen wrench to further tighten it. But it would be impossible to install the leg and leave it in a state where the leg is not secured at all and not notice it.  The leg would fall off then. 

Having just installed these new plates and bolts, I will say that I'm not worried about the bolts coming loose, it simply requires too many turns of the bolt in order to not just release the leg in the case of removing it, but actually free the leg to the point of any kind of motion.  I'm not worried about sabotage FWIW.  

I find with this system. It's much easier to determine if a leg is secured than going around with a rubber mallet, whacking the inside of the leg to make sure that the interlocking leg plates are secure. But YMMV and if there's any doubt I think it's probably best to discuss this with Steinway directly. I can't really offer more than that here.  

Honestly, I think we're venturing into the area of an abundance of over caution. 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

David and Daniel, thank you for the details on a nice design for grand leg attachment. Plus you clarified that no redesign is being planned (except perhaps for their consolidation). I only have two remaining items of interest that I will outline below and for which I would appreciate your feedback.

A couple important assumptions I will use below are (a) a caster that has a 2 ½" offset of the floor bearing point to dead center of the leg (as Daniel indicated), and (b) that the smaller dimension (width) of the upper part of a leg is less than twice the offset of the caster, or less than 5.0" in this assumed case. If the second assumption is not true, then you can probably ignore the Testing item of interest below.

(a - Moving) Unfortunately, leg parts are susceptible to mishandling and failure by piano moving staff whose power driver tools can (easily) accidentally be set to too high a torque. We (the piano tuner-technician) will validate proper leg attachment using an 8mm hex wrench to check for a "snug" tightness of the leg bracket's cap screw as Daniel indicates. If there is an issue from a move of damage to the leg attachment assembly, we will likely be called upon to help resolve responsibility.

(b - Testing) I am interested in whether there is a possible subjectivity and variability in checking the locking cap screw tightness for being "snug". If the caster happens to be randomly at an undesirable angle on the floor, the stationery leg torque of 825 inch-pounds (69 foot-pounds) could conceivably be opposing the cap screw that is pulling the leg locking plate into the frustrum by attempting to pull the locking plate in the opposite (unengaged) direction.

So there could be two levels of "snugness" for the locking cap screw – (i) one with zero foot-pounds of leg torque on the leg locking plate such as when the leg center of support is within the top wood flange of the leg or before the piano is set in place, and (ii) one with 825 inch-pounds of leg torque pushing or pulling the leg locking plate. In the latter case I assume that the piano tech MUST NOT first loosen the locking cap screw before re-tightening it (to check for snugness) since the locking plate might likely shift in the frustrum in the process. It will also be more difficult to tighten the locking cap screw in this (ii) instance versus (i). I'm therefore not sure how easy it will be to test for the snugness that Daniel refers to.

Take the rear piano leg as an example. If I understand the design of the new leg attachment parts correctly, case (i) above would occur when the caster is offset to the front / keyboard of the piano, while case (ii) above would occur when the caster is offset toward the rear of the piano. Regards, Norman.

Rather than us idly speculating on design failure possibilities, I suggest talk to Steinway if you have concerns. They recently reengineered these plates (I'm told!). The bolts don't appear to take much, if any, of the load or stress from moving the piano. They simply move the locking mechanism in place. It takes several turns of the bolt to tighten the mechanism such that any failure from the bolt coming loose seems very unlikely. I suppose it's possible that someone could finger tighten them and not use an Allen wrench to further tighten it. But it would be impossible to install the leg and leave it in a state where the leg is not secured at all and not notice it.  The leg would fall off then. 

Having just installed these new plates and bolts, I will say that I'm not worried about the bolts coming loose, it simply requires too many turns of the bolt in order to not just release the leg in the case of removing it, but actually free the leg to the point of any kind of motion.  I'm not worried about sabotage FWIW.  

I find with this system. It's much easier to determine if a leg is secured than going around with a rubber mallet, whacking the inside of the leg to make sure that the interlocking leg plates are secure. But YMMV and if there's any doubt I think it's probably best to discuss this with Steinway directly. I can't really offer more than that here.  

Honestly, I think we're venturing into the area of an abundance of over caution. 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

David and Daniel, thank you for the details on a nice design for grand leg attachment. Plus you clarified that no redesign is being planned (except perhaps for their consolidation). I only have two remaining items of interest that I will outline below and for which I would appreciate your feedback.

A couple important assumptions I will use below are (a) a caster that has a 2 ½" offset of the floor bearing point to dead center of the leg (as Daniel indicated), and (b) that the smaller dimension (width) of the upper part of a leg is less than twice the offset of the caster, or less than 5.0" in this assumed case. If the second assumption is not true, then you can probably ignore the Testing item of interest below.

(a - Moving) Unfortunately, leg parts are susceptible to mishandling and failure by piano moving staff whose power driver tools can (easily) accidentally be set to too high a torque. We (the piano tuner-technician) will validate proper leg attachment using an 8mm hex wrench to check for a "snug" tightness of the leg bracket's cap screw as Daniel indicates. If there is an issue from a move of damage to the leg attachment assembly, we will likely be called upon to help resolve responsibility.

(b - Testing) I am interested in whether there is a possible subjectivity and variability in checking the locking cap screw tightness for being "snug". If the caster happens to be randomly at an undesirable angle on the floor, the stationery leg torque of 825 inch-pounds (69 foot-pounds) could conceivably be opposing the cap screw that is pulling the leg locking plate into the frustrum by attempting to pull the locking plate in the opposite (unengaged) direction.

So there could be two levels of "snugness" for the locking cap screw – (i) one with zero foot-pounds of leg torque on the leg locking plate such as when the leg center of support is within the top wood flange of the leg or before the piano is set in place, and (ii) one with 825 inch-pounds of leg torque pushing or pulling the leg locking plate. In the latter case I assume that the piano tech MUST NOT first loosen the locking cap screw before re-tightening it (to check for snugness) since the locking plate might likely shift in the frustrum in the process. It will also be more difficult to tighten the locking cap screw in this (ii) instance versus (i). I'm therefore not sure how easy it will be to test for the snugness that Daniel refers to.

Take the rear piano leg as an example. If I understand the design of the new leg attachment parts correctly, case (i) above would occur when the caster is offset to the front / keyboard of the piano, while case (ii) above would occur when the caster is offset toward the rear of the piano. Regards, Norman.

Rather than us idly speculating on design failure possibilities, I suggest talk to Steinway if you have concerns. They recently reengineered these plates (I'm told!). The bolts don't appear to take much, if any, of the load or stress from moving the piano. They simply move the locking mechanism in place. It takes several turns of the bolt to tighten the mechanism such that any failure from the bolt coming loose seems very unlikely. I suppose it's possible that someone could finger tighten them and not use an Allen wrench to further tighten it. But it would be impossible to install the leg and leave it in a state where the leg is not secured at all and not notice it.  The leg would fall off then. 

Having just installed these new plates and bolts, I will say that I'm not worried about the bolts coming loose, it simply requires too many turns of the bolt in order to not just release the leg in the case of removing it, but actually free the leg to the point of any kind of motion.  I'm not worried about sabotage FWIW.  

I find with this system. It's much easier to determine if a leg is secured than going around with a rubber mallet, whacking the inside of the leg to make sure that the interlocking leg plates are secure. But YMMV and if there's any doubt I think it's probably best to discuss this with Steinway directly. I can't really offer more than that here.  

Honestly, I think we're venturing into the area of an abundance of over caution. 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Forgive me for thinking this should go without saying, but never service a piano leg while it is bearing the weight of the piano.

20nm is the torque spec for the bolt that joins the plates together. 

David and Daniel, thank you for the details on a nice design for grand leg attachment. Plus you clarified that no redesign is being planned (except perhaps for their consolidation). I only have two remaining items of interest that I will outline below and for which I would appreciate your feedback.

A couple important assumptions I will use below are (a) a caster that has a 2 ½" offset of the floor bearing point to dead center of the leg (as Daniel indicated), and (b) that the smaller dimension (width) of the upper part of a leg is less than twice the offset of the caster, or less than 5.0" in this assumed case. If the second assumption is not true, then you can probably ignore the Testing item of interest below.

(a - Moving) Unfortunately, leg parts are susceptible to mishandling and failure by piano moving staff whose power driver tools can (easily) accidentally be set to too high a torque. We (the piano tuner-technician) will validate proper leg attachment using an 8mm hex wrench to check for a "snug" tightness of the leg bracket's cap screw as Daniel indicates. If there is an issue from a move of damage to the leg attachment assembly, we will likely be called upon to help resolve responsibility.

(b - Testing) I am interested in whether there is a possible subjectivity and variability in checking the locking cap screw tightness for being "snug". If the caster happens to be randomly at an undesirable angle on the floor, the stationery leg torque of 825 inch-pounds (69 foot-pounds) could conceivably be opposing the cap screw that is pulling the leg locking plate into the frustrum by attempting to pull the locking plate in the opposite (unengaged) direction.

So there could be two levels of "snugness" for the locking cap screw – (i) one with zero foot-pounds of leg torque on the leg locking plate such as when the leg center of support is within the top wood flange of the leg or before the piano is set in place, and (ii) one with 825 inch-pounds of leg torque pushing or pulling the leg locking plate. In the latter case I assume that the piano tech MUST NOT first loosen the locking cap screw before re-tightening it (to check for snugness) since the locking plate might likely shift in the frustrum in the process. It will also be more difficult to tighten the locking cap screw in this (ii) instance versus (i). I'm therefore not sure how easy it will be to test for the snugness that Daniel refers to.

Take the rear piano leg as an example. If I understand the design of the new leg attachment parts correctly, case (i) above would occur when the caster is offset to the front / keyboard of the piano, while case (ii) above would occur when the caster is offset toward the rear of the piano. Regards, Norman.

Rather than us idly speculating on design failure possibilities, I suggest talk to Steinway if you have concerns. They recently reengineered these plates (I'm told!). The bolts don't appear to take much, if any, of the load or stress from moving the piano. They simply move the locking mechanism in place. It takes several turns of the bolt to tighten the mechanism such that any failure from the bolt coming loose seems very unlikely. I suppose it's possible that someone could finger tighten them and not use an Allen wrench to further tighten it. But it would be impossible to install the leg and leave it in a state where the leg is not secured at all and not notice it.  The leg would fall off then. 

Having just installed these new plates and bolts, I will say that I'm not worried about the bolts coming loose, it simply requires too many turns of the bolt in order to not just release the leg in the case of removing it, but actually free the leg to the point of any kind of motion.  I'm not worried about sabotage FWIW.  

I find with this system. It's much easier to determine if a leg is secured than going around with a rubber mallet, whacking the inside of the leg to make sure that the interlocking leg plates are secure. But YMMV and if there's any doubt I think it's probably best to discuss this with Steinway directly. I can't really offer more than that here.  

Honestly, I think we're venturing into the area of an abundance of over caution. 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Daniel, OK -- "never service a [Steinway] piano leg while it is bearing the weight of the piano". Yes, as we discussed, there are extra stresses involved with large offset casters which can "interact" with the new type of Steinway leg attachment hardware.

What about normal service to our customers with Steinway grands to include validation of an installation or a move, normal extra service upon a tuning, or upon doing an appraisal? Do we service the old leg attachment part number as we always have? What particular service guidance does Steinway provide for these situations outlined when the new style leg attachment hardware is involved? For example, from David's posting, and from your experience of piano movers having impact screw drivers (that can far exceed the 20 foot-pound spec for the new leg locking plate bolt), we are expecting some stripped locking assemblies upon moves. Regards, Norman.

Forgive me for thinking this should go without saying, but never service a piano leg while it is bearing the weight of the piano.

20nm is the torque spec for the bolt that joins the plates together. 

David and Daniel, thank you for the details on a nice design for grand leg attachment. Plus you clarified that no redesign is being planned (except perhaps for their consolidation). I only have two remaining items of interest that I will outline below and for which I would appreciate your feedback.

A couple important assumptions I will use below are (a) a caster that has a 2 ½" offset of the floor bearing point to dead center of the leg (as Daniel indicated), and (b) that the smaller dimension (width) of the upper part of a leg is less than twice the offset of the caster, or less than 5.0" in this assumed case. If the second assumption is not true, then you can probably ignore the Testing item of interest below.

(a - Moving) Unfortunately, leg parts are susceptible to mishandling and failure by piano moving staff whose power driver tools can (easily) accidentally be set to too high a torque. We (the piano tuner-technician) will validate proper leg attachment using an 8mm hex wrench to check for a "snug" tightness of the leg bracket's cap screw as Daniel indicates. If there is an issue from a move of damage to the leg attachment assembly, we will likely be called upon to help resolve responsibility.

(b - Testing) I am interested in whether there is a possible subjectivity and variability in checking the locking cap screw tightness for being "snug". If the caster happens to be randomly at an undesirable angle on the floor, the stationery leg torque of 825 inch-pounds (69 foot-pounds) could conceivably be opposing the cap screw that is pulling the leg locking plate into the frustrum by attempting to pull the locking plate in the opposite (unengaged) direction.

So there could be two levels of "snugness" for the locking cap screw – (i) one with zero foot-pounds of leg torque on the leg locking plate such as when the leg center of support is within the top wood flange of the leg or before the piano is set in place, and (ii) one with 825 inch-pounds of leg torque pushing or pulling the leg locking plate. In the latter case I assume that the piano tech MUST NOT first loosen the locking cap screw before re-tightening it (to check for snugness) since the locking plate might likely shift in the frustrum in the process. It will also be more difficult to tighten the locking cap screw in this (ii) instance versus (i). I'm therefore not sure how easy it will be to test for the snugness that Daniel refers to.

Take the rear piano leg as an example. If I understand the design of the new leg attachment parts correctly, case (i) above would occur when the caster is offset to the front / keyboard of the piano, while case (ii) above would occur when the caster is offset toward the rear of the piano. Regards, Norman.

Rather than us idly speculating on design failure possibilities, I suggest talk to Steinway if you have concerns. They recently reengineered these plates (I'm told!). The bolts don't appear to take much, if any, of the load or stress from moving the piano. They simply move the locking mechanism in place. It takes several turns of the bolt to tighten the mechanism such that any failure from the bolt coming loose seems very unlikely. I suppose it's possible that someone could finger tighten them and not use an Allen wrench to further tighten it. But it would be impossible to install the leg and leave it in a state where the leg is not secured at all and not notice it.  The leg would fall off then. 

Having just installed these new plates and bolts, I will say that I'm not worried about the bolts coming loose, it simply requires too many turns of the bolt in order to not just release the leg in the case of removing it, but actually free the leg to the point of any kind of motion.  I'm not worried about sabotage FWIW.  

I find with this system. It's much easier to determine if a leg is secured than going around with a rubber mallet, whacking the inside of the leg to make sure that the interlocking leg plates are secure. But YMMV and if there's any doubt I think it's probably best to discuss this with Steinway directly. I can't really offer more than that here.  

Honestly, I think we're venturing into the area of an abundance of over caution. 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------

Norman, I think you are worrying about this overmuch. Perhaps you've never seen a broken traditional leg plate but I have, in fact the rear end of a 'D' once collapsed and missed my young apprentice toes by inches. As far as inspecting a grand, it's hard to tell the exact condition of a caul or whether or not its screw is secure or bent or if the plate screws are tight when the piano is set up or even if the right leg is in the right position. I've worked on some pretty rickety/scary pianos with the old plate and caul system. 

This "new" system has been used for almost 20 years, I did a search on the forum and this is the first failure noted. I don't think it's worth losing sleep over.

Daniel, OK -- "never service a [Steinway] piano leg while it is bearing the weight of the piano". Yes, as we discussed, there are extra stresses involved with large offset casters which can "interact" with the new type of Steinway leg attachment hardware.

What about normal service to our customers with Steinway grands to include validation of an installation or a move, normal extra service upon a tuning, or upon doing an appraisal? Do we service the old leg attachment part number as we always have? What particular service guidance does Steinway provide for these situations outlined when the new style leg attachment hardware is involved? For example, from David's posting, and from your experience of piano movers having impact screw drivers (that can far exceed the 20 foot-pound spec for the new leg locking plate bolt), we are expecting some stripped locking assemblies upon moves. Regards, Norman.

Forgive me for thinking this should go without saying, but never service a piano leg while it is bearing the weight of the piano.

20nm is the torque spec for the bolt that joins the plates together. 

David and Daniel, thank you for the details on a nice design for grand leg attachment. Plus you clarified that no redesign is being planned (except perhaps for their consolidation). I only have two remaining items of interest that I will outline below and for which I would appreciate your feedback.

A couple important assumptions I will use below are (a) a caster that has a 2 ½" offset of the floor bearing point to dead center of the leg (as Daniel indicated), and (b) that the smaller dimension (width) of the upper part of a leg is less than twice the offset of the caster, or less than 5.0" in this assumed case. If the second assumption is not true, then you can probably ignore the Testing item of interest below.

(a - Moving) Unfortunately, leg parts are susceptible to mishandling and failure by piano moving staff whose power driver tools can (easily) accidentally be set to too high a torque. We (the piano tuner-technician) will validate proper leg attachment using an 8mm hex wrench to check for a "snug" tightness of the leg bracket's cap screw as Daniel indicates. If there is an issue from a move of damage to the leg attachment assembly, we will likely be called upon to help resolve responsibility.

(b - Testing) I am interested in whether there is a possible subjectivity and variability in checking the locking cap screw tightness for being "snug". If the caster happens to be randomly at an undesirable angle on the floor, the stationery leg torque of 825 inch-pounds (69 foot-pounds) could conceivably be opposing the cap screw that is pulling the leg locking plate into the frustrum by attempting to pull the locking plate in the opposite (unengaged) direction.

So there could be two levels of "snugness" for the locking cap screw – (i) one with zero foot-pounds of leg torque on the leg locking plate such as when the leg center of support is within the top wood flange of the leg or before the piano is set in place, and (ii) one with 825 inch-pounds of leg torque pushing or pulling the leg locking plate. In the latter case I assume that the piano tech MUST NOT first loosen the locking cap screw before re-tightening it (to check for snugness) since the locking plate might likely shift in the frustrum in the process. It will also be more difficult to tighten the locking cap screw in this (ii) instance versus (i). I'm therefore not sure how easy it will be to test for the snugness that Daniel refers to.

Take the rear piano leg as an example. If I understand the design of the new leg attachment parts correctly, case (i) above would occur when the caster is offset to the front / keyboard of the piano, while case (ii) above would occur when the caster is offset toward the rear of the piano. Regards, Norman.

Rather than us idly speculating on design failure possibilities, I suggest talk to Steinway if you have concerns. They recently reengineered these plates (I'm told!). The bolts don't appear to take much, if any, of the load or stress from moving the piano. They simply move the locking mechanism in place. It takes several turns of the bolt to tighten the mechanism such that any failure from the bolt coming loose seems very unlikely. I suppose it's possible that someone could finger tighten them and not use an Allen wrench to further tighten it. But it would be impossible to install the leg and leave it in a state where the leg is not secured at all and not notice it.  The leg would fall off then. 

Having just installed these new plates and bolts, I will say that I'm not worried about the bolts coming loose, it simply requires too many turns of the bolt in order to not just release the leg in the case of removing it, but actually free the leg to the point of any kind of motion.  I'm not worried about sabotage FWIW.  

I find with this system. It's much easier to determine if a leg is secured than going around with a rubber mallet, whacking the inside of the leg to make sure that the interlocking leg plates are secure. But YMMV and if there's any doubt I think it's probably best to discuss this with Steinway directly. I can't really offer more than that here.  

Honestly, I think we're venturing into the area of an abundance of over caution. 

Parker, I'm not qualified to make definitive decisions / observations on this topic, but I personally have the same opinion you have. In light of David's findings on the stress that this new part is subjected to, I think that the manufacturer should consider a re-evaluation. If they decide to stay with the same type of design, rather than perhaps to revert back to the old part, I suspect they would enhance the strength of both the screw and the threaded plate. A #10 (hex head) machine screw size (about 5/16" diameter?), if I have it right, seems a little small if the piano movers incorrectly have their driver torque set all the way up. Of course a more robust screw and threaded plate could involve a more extensive redesign of the whole part.

David, I am afraid that I disagree with your opinion that we should plan on being alert for a loose leg attachment by watching for a wobble of the leg. My opinion is DO NOT test (or observe) using a wobble as a criteria, with the explanation being as follows. Let's assume that the wooden plate at the top of the rear leg measures 5" x 15". (I got this from a different brand of piano – just using it here for talking purposes.) The modern concert grand brass caster offset from dead center appears to run around 1 7/8" from what I see in part catalogs. Assume that the caster on the rear leg is (randomly) pointed toward the keyboard (with its floor bearing point / line then being 5/8" behind the front edge of the upper leg wooden plate) – and the caster might further be locked or for whatever reason assume that it does not easily rotate. If the rear leg is not properly attached to the piano body, and if there is then a "wobble" that allows the keyboard to be pushed forward more than 5/8", the upper part of the rear leg could be buckled forward such that its front support edge is pushed beyond the position vertically above the floor bearing point of the caster – and of course then the rear leg could then start to tip forward disastrously / catastrophically.

To summarize: A Steinway concert grand with large brass casters can become unstable if the mechanism holding a leg to the piano body is compromised, such as its locking apron being incorrectly adjusted by piano movers. The problem can be exacerbated depending upon the position / angle of a caster on the floor! Exercise caution! 

Am I missing something? A clarification if I am wrong, including a good engineering explanation, would be appreciated. Regards, Norman.

------------------------------
Norman Brickman
Potomac Piano Service
Potomac, Maryland
potomacpiano@verizon.net
https://potomacpiano.com
(301) 983.9321

Original Message:
Sent: 01-26-2025 08:03
From: Leslie Koltvedt
Subject: Hamburg Steinway Leg Repair

Cap bolts are understood in the automotive field as grade 8 bolts.
Les Koltvedt
(404) 631-7177
LKPianos.com


Original Message:
Sent: 1/25/2025 4:26:00 PM
From: David Love
Subject: RE: Hamburg Steinway Leg Repair

The problem wasn't the bolts, They are hardened steel, pretty durable.  In fact, I reused the bolt on the new plates.  The problem was the threads on the plates which were stripped out.  The bolts involved in the stripped threads on the plates emerged unscathed.  .  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 01-25-2025 11:57
From: Parker Leigh
Subject: Hamburg Steinway Leg Repair

I wonder if it might make sense to have a larger diameter bolt say 10 or 12 mm and of higher strength given the stresses involved.

------------------------------
Parker Leigh RPT
Winchester VA
(540) 722-3865

Original Message:
Sent: 12-26-2024 16:35
From: David Love
Subject: Hamburg Steinway Leg Repair

I have a Hamburg Steinway B that I'm working on.  The Threaded leg socket and set screw both seem to be stripped.  Probably have to replace the threaded socket  imbedded in the leg.  Has anyone actually done this specific job who can advise on removing the old socket?

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320
------------------------------