CAUT

I'm installing a new Stwy back action in a 1920 M, and following David Hughes' excellent protocols, measured the old and new distances (to the keybed front) of the underlever noses and sostenuto tabs. It turns out that the new tabs have moved 1/4" forward from the old tabs. This was confirmed by trying to regulate the sostenuto (with the action unchanged from its original location). To get the lip to engage the tabs by 1/16" during a proper regulation, the rod and its brackets do have to be moved back by 1/4".

So how to recover the 1/4" lost to the backcheck/sostenuto clearance in this situation. If I move the entire back action back so that the new tabs match the location of the old, the pick-up point of the underlevers on the key end felt moves from 50% of the key end length to 20% ( - at 0% you fall off the end of the felt). I've never see anything like that, and can only guess at whether the wear over the years would be less, applied to the middle than towards the end. As for whether the damper posts, moving 1/4" backwards, would be far enough off of directly under their guide rail bushings to lose that advantage of damper wires traveling purely vertical…I can only guess there, too. There is room behind the damper assembly for this 1/4" move.

The other idea is to do a Forstner bit cove in the backside of the backcheck head. (This action is getting new backchecks and wires.) In the accompanying photo, there are two 5/16" arcs, one going 1/4' into the head and the other, 1/8". Clearly, the 100% solution (asking the backcheck head to cough up the missing 1/4") doesn't leave enough thickness to convince me that the head won't crack under heavy use. But the 50% solution (1/8" into the head looks do-able). (Assuming that the backcheck wire will be clear of the cove.)

So I'm thinking the best way out of this situation is to get an 1/8" from both of these locations.

Anyone else been in this situation? And come up with a better solution? (I thought for a while that converting to the Hamburg belly-rail-mounted sostenuto might work, but that's out of the question.)


------------------------------
William Ballard RPT
WBPS
Saxtons River VT
802-869-9107

"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The continental Harmony,1774
+++++++++++++++++++++
------------------------------

Original Message------

I'm installing a new Stwy back action in a 1920 M, and following David Hughes' excellent protocols, measured the old and new distances (to the keybed front) of the underlever noses and sostenuto tabs. It turns out that the new tabs have moved 1/4" forward from the old tabs. This was confirmed by trying to regulate the sostenuto (with the action unchanged from its original location). To get the lip to engage the tabs by 1/16" during a proper regulation, the rod and its brackets do have to be moved back by 1/4".

So how to recover the 1/4" lost to the backcheck/sostenuto clearance in this situation. If I move the entire back action back so that the new tabs match the location of the old, the pick-up point of the underlevers on the key end felt moves from 50% of the key end length to 20% ( - at 0% you fall off the end of the felt). I've never see anything like that, and can only guess at whether the wear over the years would be less, applied to the middle than towards the end. As for whether the damper posts, moving 1/4" backwards, would be far enough off of directly under their guide rail bushings to lose that advantage of damper wires traveling purely vertical…I can only guess there, too. There is room behind the damper assembly for this 1/4" move.

The other idea is to do a Forstner bit cove in the backside of the backcheck head. (This action is getting new backchecks and wires.) In the accompanying photo, there are two 5/16" arcs, one going 1/4' into the head and the other, 1/8". Clearly, the 100% solution (asking the backcheck head to cough up the missing 1/4") doesn't leave enough thickness to convince me that the head won't crack under heavy use. But the 50% solution (1/8" into the head looks do-able). (Assuming that the backcheck wire will be clear of the cove.)

So I'm thinking the best way out of this situation is to get an 1/8" from both of these locations.

Anyone else been in this situation? And come up with a better solution? (I thought for a while that converting to the Hamburg belly-rail-mounted sostenuto might work, but that's out of the question.)


------------------------------
William Ballard RPT
WBPS
Saxtons River VT
802-869-9107

"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The continental Harmony,1774
+++++++++++++++++++++
------------------------------

I had this experience with a 1911 O and Renner back action kit, although less severe.  Solved by coving backchecks with spindle sander, photo attached.   I cannot see how a replacement blade could give you the 1/4" you need.  Perhaps replacing the old backchecks with a more compact part will give you enough clearance.  If you relocate the back action closer to the belly rail, you'll have to do some wire bending to maintain wire verticality through the guide rail.  Another thought/caution:   If I remember correctly, there was something funny about the belly rail and original back action, like neither one was parallel to the keybed edge, and I had to remove some material from the back of the new tray at one end to eliminate interference with the belly rail.  Good luck, and let us know how you end up fixing it.

------------------------------
Michael Spalding
Fredonia WI
262-692-3943
------------------------------

Original Message:
Sent: 03-22-2017 22:42
From: William Ballard
Subject: With new Stwy Back Action, No Backcheck Clearance

I'm installing a new Stwy back action in a 1920 M, and following David Hughes' excellent protocols, measured the old and new distances (to the keybed front) of the underlever noses and sostenuto tabs. It turns out that the new tabs have moved 1/4" forward from the old tabs. This was confirmed by trying to regulate the sostenuto (with the action unchanged from its original location). To get the lip to engage the tabs by 1/16" during a proper regulation, the rod and its brackets do have to be moved back by 1/4".

So how to recover the 1/4" lost to the backcheck/sostenuto clearance in this situation. If I move the entire back action back so that the new tabs match the location of the old, the pick-up point of the underlevers on the key end felt moves from 50% of the key end length to 20% ( - at 0% you fall off the end of the felt). I've never see anything like that, and can only guess at whether the wear over the years would be less, applied to the middle than towards the end. As for whether the damper posts, moving 1/4" backwards, would be far enough off of directly under their guide rail bushings to lose that advantage of damper wires traveling purely vertical…I can only guess there, too. There is room behind the damper assembly for this 1/4" move.

The other idea is to do a Forstner bit cove in the backside of the backcheck head. (This action is getting new backchecks and wires.) In the accompanying photo, there are two 5/16" arcs, one going 1/4' into the head and the other, 1/8". Clearly, the 100% solution (asking the backcheck head to cough up the missing 1/4") doesn't leave enough thickness to convince me that the head won't crack under heavy use. But the 50% solution (1/8" into the head looks do-able). (Assuming that the backcheck wire will be clear of the cove.)

So I'm thinking the best way out of this situation is to get an 1/8" from both of these locations.

Anyone else been in this situation? And come up with a better solution? (I thought for a while that converting to the Hamburg belly-rail-mounted sostenuto might work, but that's out of the question.)


------------------------------
William Ballard RPT
WBPS
Saxtons River VT
802-869-9107

"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The continental Harmony,1774
+++++++++++++++++++++
------------------------------

Original Message------

I had this experience with a 1911 O and Renner back action kit, although less severe.  Solved by coving backchecks with spindle sander, photo attached.   I cannot see how a replacement blade could give you the 1/4" you need.  Perhaps replacing the old backchecks with a more compact part will give you enough clearance.  If you relocate the back action closer to the belly rail, you'll have to do some wire bending to maintain wire verticality through the guide rail.  Another thought/caution:   If I remember correctly, there was something funny about the belly rail and original back action, like neither one was parallel to the keybed edge, and I had to remove some material from the back of the new tray at one end to eliminate interference with the belly rail.  Good luck, and let us know how you end up fixing it.

------------------------------
Michael Spalding
Fredonia WI
262-692-3943
------------------------------

Debbie said:

Mark Dierauf also mentioned the Tokiwa advantage. But that'll be for next time. This time, it's the Stwy d'assy. I wanted to find out just how much a "drop-in-place" replacement the Stwy version was. (Boy, am I getting an answer…)

Michael said:
"If you relocate the back action closer to the belly rail, you'll have to do some wire bending to maintain wire verticality through the guide rail.

I'm prepared for that. I'm also assuming that the small 1/8" move will make maintaining verticality easy.

Another thought/caution: If I remember correctly, there was something funny about the belly rail and original back action, like neither one was parallel to the keybed edge, and I had to remove some material from the back of the new tray at one end to eliminate interference with the belly rail."

Even in an M, the belly rail and the keybed edge are parallel. All I want to do is get the new tabs where the old ones were.

"Good luck, and let us know how you end up fixing it."

I've probably got the best solution: split the 1/4" between coving the checks and moving the back action. I just wanted to make sure I wasn't overlooking a potential disaster.

Remember folks, you saw it here first.

------------------------------
William Ballard RPT
WBPS
Saxtons River VT
802-869-9107

"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The continental Harmony,1774
+++++++++++++++++++++
------------------------------

Original Message:
Sent: 03-23-2017 09:32
From: Debbie Cyr
Subject: With new Stwy Back Action, No Backcheck Clearance

We've gone to using the Tokiwa backactions, specifically to eliminate this problem.

In the past when using Renner or Steinway back actions, we've coved the backchecks.  Works, but .....

With the Tokiwa, they have 3 variations of back actions - one for replacing teflon era, one for replacing the rigid tab Steinways, and one for old Mason Hamlins.  The rigid tab system is what you want, even if your old back action didn't have rigid tabs.  They have inverted the tab on the post, and it makes all the difference in the world!  A joy to replace and regulate!  No need to cove backchecks, or monkey with the blade!

Debbie Cyr Registered piano Technician 508-202-2862 cell/text debbiecyr@me.com www.nbss.edu