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Steinway D String Bearing Assemblies

  • 1.  Steinway D String Bearing Assemblies

    Posted 02-21-2017 10:32
    I'm getting ready to restring our 1969 Steinway D.  Some improvisation apparently took place back in about 1990 when this was done last, so I don't have an original Steinway set-up to imitate.

    I am working to renew the string bearing assemblies (cloth wrapped) between the agraffes and the tuning pins in the bass and midrange of the piano.  I have the stringing cloth and felt set from Steinway, and the assemblies that I took out of the piano have the right basic shape when viewed from the top (edge curves and all) but the core around which the cloth is wrapped gives the appearance of being non -original.  The material I would describe as being a reddish brown, cardboardish looking plastic material (resin reinforced fiber?) about .045" thick, with a single thickness being used on the upper two of these three sections, and with a double thickness on the edge of the bass assembly that is oriented toward the tuning pins.

    My real question is:  What would have been there for a core originally?  Wood?  Cardboard? Resin reinforced fiber?  Am I looking a something pretty close to the original, or not?

    I sent an email to Steinway before the weekend, but haven't heard back from them yet.

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    Floyd Gadd
    Regina SK
    306-721-9699
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  • 2.  RE: Steinway D String Bearing Assemblies

    Posted 02-21-2017 10:47

    I use the file folders that have the flexible   metal strip that you fold over, and then slide those clips over the strip. They're usually brown or red. I get them from an office supply.






  • 3.  RE: Steinway D String Bearing Assemblies

    Posted 02-21-2017 11:55
    Replace the counter bearing drag strip with a brass half-round. Felt placed between that and the agraffes with a thickness to muffle the segment and not cause drag.



    Also file and polish the counter bearings in the treble sections.

    You could do the same for the bass c/b (which Ron N said he did) or cover it with firm bushing cloth.

    ------------------------------
    Regards,

    Jon Page
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  • 4.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-21-2017 11:56
    Great!  Looks really nice!

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    Paul T. Williams RPT
    Director of Piano Services
    School of Music
    813 Assembly St
    University of South Carolina
    Columbia, SC 29208
    pwilliams@mozart.sc.edu
    ------------------------------



  • 5.  RE: Steinway D String Bearing Assemblies

    Posted 02-21-2017 14:32
    I'm wrapping thin bushing cloth over co-polymer, or using co-polymer bare with a 1/4 wide piece of soft felt on the tuning pin sides. The ski slope is still there, but reduced in width a little.

    I used to use the brass half rounds, but I like the way these copolymer assemblies render way better than the brass, especially setting the brass that far away from the agraffe. I find the large distance between agraffe and brass round gives you a third segment to equalize.


     

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 6.  RE: Steinway D String Bearing Assemblies

    Posted 02-21-2017 15:58
    C'mon guys. Pianotech discussion group? This is a public space. We are supposed to understand the piano industry, and inform our clients as PTG members.

    Thee most competitively priced concert grand on the market, bar none. That is, if the local dealer did not lease it to the orchestra for free...

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    Benjamin Sloane
    Cincinnati OH
    513-257-8480
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  • 7.  RE: Steinway D String Bearing Assemblies

    Posted 02-21-2017 17:32
    Thank you all for the input thus far.

    Can anyone tell me how these strips were originally set up?  I now have a couple of ideas for varying the original configuration, but I have yet to establish what the original configuration was.  I've not restrung a Steinway before, and this one was monkeyed with years before it came under my care.

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    Floyd Gadd
    Regina SK
    306-721-9699
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  • 8.  RE: Steinway D String Bearing Assemblies

    Posted 02-21-2017 19:41
    Glueing the felt to the fiber board is a two stage operation. First you have to glue the felt to the flat top portion. Next day, glue the edges. I use masking tape pinched together at the bottom of the board to hold the felt to the edge, overlap tape for the full length so you don't get bulges.
    Trim the felt flush with the bottom and don't fold it under. If you have to go that route.

    ------------------------------
    Regards,

    Jon Page
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  • 9.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 02:01
    Well,
    We use mics for tuning. Why not for results damping the front uniduplitriplex?

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    Benjamin Sloane
    Cincinnati OH
    513-257-8480
    ------------------------------



  • 10.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-22-2017 07:13

    I'm pretty sure that the original bushing cloth wasn't glued to the top surface of the fiberboard. The front and back edges are tucked underneath and glued to the lower edges. Do one side, let the glue dry, then stretch the material around and glue down the other edge. I've used strips of waxed paper wrapped tightly around the piece to hold the cloth in position and lay a heavy flat weight on top while it cures.

     

    Sent from Mail for Windows 10

     






  • 11.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 08:39
    Mark Dierauf< I'm pretty sure that the original bushing cloth wasn't glued to the top surface of the fiberboard. 

    This makes a lot of sense, and is something I also pay a lot of attention to when setting up bearing conditions.  Especially if its a tacky substance like contact cement or PVCE...or frankly any glue. Drag over the felt is a problem for tuning, and substrate materials effect this drag. 

    What is under the felt matters. Proof, in the bass (grands), I routinely, add a small strip of High density molecular plastic, the stuff they sell in woodworking catalogs to stick to table saw fences to lower friction coefficients. I do this in the bass and often in the low tenor, when there is an aggressive termination angle to come up to the pin. Thin bushing cloth on top of it. The rendering of the strings over this combination of bearing felt and slippery substrate is significantly more compliant than the usual sticky contact here.

    If I apply glue, to whatever substrate on the surface where the strings bear, I make sure to keep it away from the actual string locations.  

    I would also add, that setting up these bearings is so important to the future tun-ability of the job, that I spend a fair amount of time working out the conditions of that piano in a fashion that will be tuner friendly. This includes changing bearing angles by grinding plates, or making bearing substrates which are of different thicknesses than the manufacturer set up. As far as respecting what the manufacturer set up...if the piano was not compliant, I reconfigure this area as necessary...keeping in mind manufacturers setups here reflect the small amount of time allowed to set up bearings. In production pianos, these bearings appear to be an afterthought for most manufacturers. Their bearing conditions are often not conducive to compliant tuning.

    Its actually a deceptively difficult area to get right.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 12.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 09:09

    Hi Jim,
    Fascinating topic! How did you determine the differences of friction? And how much lower in friction was the plastic material? And how much more friction was caused by the glue versus no glue under the felt?






  • 13.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 22:10
    Chris< How did you determine the differences of friction?

    By feel...that is, by using the highly developed sense, which is about...i don't know...say...70% of what we do  when tuning...ie read the movement of the string over the bearings and termination points. We spend most of our tuning time reading these differences. We can tell how the string is moving with amazing accuracy, proven by the stability of out best tunings. Do I have numbers...nope.

    And how much lower in friction was the plastic material?

    coefficient of friction  steel on brass .35, steel on PTFE .05-.2, clean metal on wood  .2-.6, Zinc on cast iron .85, Steel on leather (closest I could find to felt) .4-.6.  The PTFE, at its worst is 1/2 the coefficient of friction of steel on brass, and at the best 1/7.

    And how much more friction was caused by the glue versus no glue under the felt? 

    I have no clue. But lets ask a different question. Why would one put a sticky substance, like PVCE, which can be reactivated by water, under felt which absorbs water from the atmposhere? What are the chances of this glue reactivating, then, under pressure of the strings working its way through a shy millimeter of porous felt to the string/felt interface.  Or why put contact cement which remains sticky under the felt in this same proximity...are we sure it will not migrate under pressure, encouraged by dampness?


    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 14.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-22-2017 09:11
    Floyd,

    All the ones I have ever seen have been glued to the top and edges but not underneath (Yamaha does that in their copy version). From your description, I believe you have the originals. If they are reasonably flat on the bottom and slightly arched on the top that should be correct. At least two options: 

    1) Easy way...trash it and replace it with firm 1/4" stringing felt as in the Hamburg model. I have done this once in 40+ years with no issues.

    2) Hard way...duplicate. I wrestled with this for many years until I finally arrived at a jig to do it foolproof. You can do this. After removing the old stuff, cut a piece of bushing cloth big enough that it will wrap all the way around the fiberboard and then some (yes...I can hear it already...waste, waste, waste). You need enough so you can pull it tight all around the edges and use strong spring clamps to hold it in place till it dries. (Roughly 3 times what will ultimately remain).

    Apply hot hide glue to the top surface AND edges (not the ends). Put the "mold" in the center and pull everything as tight as possible on the back side with your spring clamps. Now let it dry totally like this (at least 24 hrs is good.  Hide glue works well here because it gels fast and won't wick through the cloth and harden it. I don't think there is anything else that will work).

    Disassemble the clamps. Use a brand new razor blade to carefully slice off the cloth from the underside LEAVING it curled around the edges, but not underneath. Trim the ends and you're good to go.

    Although a little clunky, this works pretty well. When I inquired at Steinway as to how they do it (I knew they had to have some sort of fixture for it) I was told: "It's a trade secret".   OK, thanks a lot!...so after thinking about a while I made myself a fixture that makes it much easier. Same process but no need of spring clamps. 

    Have fun!

    Pwg

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



  • 15.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-22-2017 10:03
    Jim,

    I am not quite understanding something. The idea of putting the cloth on top of the slippery stuff. How is this held in place? Strictly string pressure? Especially in the bass with a curved surface?  

    I have never seen a Steinway bearing surface NOT glued to the substrate in the tenor.

    Pwg


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



  • 16.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 10:11
    Maybe I do in fact have the original cores with replacement cloth glued on.  I'm attaching photos of a couple of them.  I guess the next step is to steam off the cloth and see what I have.

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    Floyd Gadd
    Regina SK
    306-721-9699
    ------------------------------



  • 17.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 10:52
    That does not look OEM. All the one's that I've taken apart have had the cloth glued to the top and cut flush to the bottom. Brass half-round is fairly easy to bend to the curvature of the plate.

    ------------------------------
    Regards,

    Jon Page
    ------------------------------



  • 18.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-22-2017 17:53
    Definitely the folding under is not OEM because it is so hard to get it right. However the color of the fiberboard does look to be OEM to me.

    Pwg

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



  • 19.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-22-2017 21:58
    All the ones that I have seen have the felt folded over the fiberboard. You can get fiberboard sheets from NY Steinway. I have never found it available locally.

    The old ones seem to have the felt attached to them by shellac. Newer ones use glues of different types over the years. Some have contact like cement.  I have used 3-M spray contact cement on some. I have also used Tite-bond on others. I never put glue on the top surface.

    When I use Tie-bond I also use an iron on med-low heat to press and cure the felt to the underside. Do one edge and then pull the other edge tightly around the board while ironing it. The work surface and Iron must be clean.

    I do pay much attention to proper thickness so the string is supported at the agraffe edge and the tuning pin edge keeps the string off the plate surface. I also cut the shape such that the open length behind the highest agraffes is about half the length of the duplex above but tapers closer as you move down the compass. This makes a better blend with the duplex break.

    Also make sure the highest agraffe string path can be made straight to the tuning pins. Sometimes you have to thin the highest end to allow for the plate surface sloping up to the strut. On some I have to grind some of the strut side to make room for the string path.

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    Edward McMorrow
    Edmonds WA
    425-299-3431
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  • 20.  RE: Steinway D String Bearing Assemblies

    Posted 02-23-2017 09:54
    Now that I've got it apart, I see that the fiber board is not folded -- just two layers glued together.  I'm now considering it to be the original core.

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    Floyd Gadd
    Regina SK
    306-721-9699
    ------------------------------



  • 21.  RE: Steinway D String Bearing Assemblies

    Posted 02-22-2017 22:30
    Peter< The idea of putting the cloth on top of the slippery stuff. How is this held in place? Strictly string pressure? Especially in the bass with a curved surface?  

    Strings hold it in place, or you can glue the felt at the edges, as many manufactures have done in the past.

    <I have never seen a Steinway bearing surface NOT glued to the substrate in the tenor.

    And I have never seen a Steinway that was compliant to tune, in the tenor, with this setup.

    Here's a couple of pics of a Brinsmead I'm stringing today. The first one has a thin slick strip adhered to the tenor bearing area. bushing cloth will cover it, glued only at the front edge where strings are not contacting the surfaceqnH9pGgRxG9oQZDmE0eE_brinsmead1.jpg
    zyKeoxHPST22rCyqpKQm_brinsmead2.jpg
    The 3rd has straight up co-polymer , they way I set up alto and soprano sections often. This is not one of Ed Mcmorrow's FTDS duplexes, but when I do do an FTDS treble, the same type of co-polymer counter-bearing in used, with specific duplex lengths.

    ri7q0K30TWegswOL5j1d_brinsmead3.jpg   .  
    Note on this 4th pic how the co-polymer, though slick stays put quite nicely as long as the rest beneath the plastic has a slight downward slope. Just the first unison is enough to hold the polymer in place without fighting with it, while stringing.AZRL75rRCevRmn1EZegn_brinsmead4.jpg 
    These co-polymer rests have been cut as a wedge, to both form a low termination angle, and lift the string to a decent takeoff angle to the pin.


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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 22.  RE: Steinway D String Bearing Assemblies

    Posted 02-23-2017 05:44

    Hi jim
    The pics look great. You've inspired me to give this a try. Which copolymer do you recommend? And any concern or observation of cold flow?






  • 23.  RE: Steinway D String Bearing Assemblies

    Posted 02-23-2017 09:16
    <Which co-polymer do you recommend?


    Mcmaster-carr acetal co-polymer

    I bought a 3/4 x 12 x 12 last time, and bandsaw it as needed. I might consider a 1/2 thick piece next time...not sure. It machines well with woodworking tools. I prefer to bandsaw it when doing beveled rests. It doesn't like to be jointed when the piece gets too thin.

    As far as cold creep, no, I haven't noticed. Bottom line is the pianos are stable, and that is the point of this excercise. 

    By the way, I thank Ed Mcmorrow for doing the leg work on co-polymer rests. I had been thinking about this for a while, and experimenting with it, when Ed came out with his FTDS patent. When I saw he had already done the legwork on the susbstance, I was already ready to go.

    Also, I came to try this substance after numerous disappointments using brass half-rounds. I had committed myself, earlier on, based on the advice of mentors, to use the brass instead of bearing felt. However, I was very disappointed with the results, and that propelled me to look for a different solution. Based on the advice of mentors regarding brass counter-bearing bars, whenever I saw a brass half-round set up, I was in eager expectation of an easily rendering tuning experience. Unfortunately, my experience has been that these setups if not done well can be really difficult to tune, creating problems of their own (my own experience, can't speak for others). There are situations where they provide for horrible rendering. Specifically:

    -Long tenor duplex to the Brass, combined with thick dense felt on the pin side...impossible to tune...a Chinese specialty
    -Brass well up the ski slope with quieting felt in the duplex (can be soft, and only 1/4" wide but its there), and then some more 1/4" wide soft felt on the pin side. These setups usually are like this because the termination angle is quite aggressive. Foeresters have this, at least the 170 I care for has it. The long elastic length of the tenor duplexes before they hit the bar create a third segment to equalize. Very hard piano to tune. I've learned how to do it, but it can be real slow and sneaky.
    -Brass close to the agraffes to eliminate a duplex, then a second piece of brass to allow a decent string takeoff angle to the pins...awful rendering from the second friction point and elastic space between the two.

    The difficulty is often in the tenor where the ski slope makes it problematic to get decent string angle takeoff to the tuning pin. The string is lifted to achieve this string takeoff angle, and it makes life difficult. Each piano id different and it takes some thought and time to work out all the parameters. Putting a high value on compliant rendering , the co-polymer has made this design dance easier than the other options for me.
    I

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 24.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-23-2017 09:35
    Jim,

    Yes, I agree with you on the compliance issue, though in my experience it doesn't start to show up until about 10 years or more down the road, and minor lubrication usually takes care of it. I have to assume that you have some data to support that this arrangement lasts much longer.

    Can I also assume that the basic idea is that as the string is moved, the cloth also moves microscopically due to the non-adherence to the substrate, therefore somehow helping the string to break the static friction better than the "solid" arrangement?  Or is something else going on? 

    I'm all for a better design if it works. I'm also a believer in "you can't argue with results", even though I might not fully understand the underlying physics yet.

    Where do you get the black stuff. I already have a roll of clear on bought a Woodcraft.

    Pwg

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



  • 25.  RE: Steinway D String Bearing Assemblies

    Posted 02-23-2017 21:08
    Peter< though in my experience it doesn't start to show up until about 10 years or more down the road. I have to assume that you have some data to support that this arrangement lasts much longer.

    Co-polymer (Delrin-Dupont) has been around for. 50 years. Creep resistance is excellent. Test bars in storage in ambient atmospheres for 20 yrs showed no test structural changes. Weathering outside in direct exposure to UV may accelerate some degradation, but we are in controlled atmospheres.

    My take is that problems with corrosion in the steel wire will appear much faster than the co-polymer at its worst would degrade...not to mention felt degradation and problems of felt accumulating moist dust. So the co-polymer is the least of our potential worries. I am using Paullelo nickel plated wire now and for the last 2 years of so. This wire does not corrode as un-plated does...I have a test out on the clothes line now for 6 months, waiting to see what non immersion conditions do to the stuff. The plating by the way is a process which I have not been able under any circumstances, to induce flaking of any sort.

    Though I am not using any un-plated wire at this point, my bet is that, with standard Mapes or Roslau, the wire bearing on the  Co-polymer's non-hydroscopic surface, the usual corrosion we see in the interface between steel and felt will be much more favorable to longer term avoidance of rendering challenging under-string corrosion.  In the combination co-polymer/felt bearing I'm sometimes using, mostly in the tenor, this might not be as favorable as the pure un-felted co-polymer. Its interesting that the felt, which is a pain in the ass to apply, is purely for visual effect, and actually adds a superfluous albatross to the system. 

    So in answer to your question, no I only have about 3 yrs installations at this point, but have set up the conditions to slow down the usual corrosion, which is the biggest problem child in this whole rendering scenario.


    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 26.  RE: Steinway D String Bearing Assemblies

    Posted 02-23-2017 21:09
    Oh...re the link to a supplier of the co-polymer, see my link elsewhere in this thread to Chris' question. Its there, if you wade through the responses...I posted it today

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 27.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-24-2017 09:20
    Understood...and very interesting.

    Pwg

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



  • 28.  RE: Steinway D String Bearing Assemblies

    Registered Piano Technician
    Posted 02-23-2017 11:41

    This is my basic format for all Steinway pianos.  Got this idea from Del Fandrich many years ago now and the actual arrangement of the felt seems to vary a little from piano to piano but it's basically this idea.  The brass is bent by hand (not difficult) and just held in place by the pressure of the strings.  The felt between the bar and the agraffes has minimal contact (drag) with the strings.  I don't use the brass in the bass section or the treble though I have on occasion ground off the counterbearing bars and inserted a brass piece that shortens the length of those segments.  This is an old photo I've gone to a slightly smaller diameter piece of brass now.  The brass rests at the top of the sloped part of the plate in this section.  



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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 29.  RE: Steinway D String Bearing Assemblies

    Posted 10-29-2020 12:56
    Jim, you requested an update. 

    I wrapped the counterbearing assemblies in cloth from Steinway, applying glue only to the underside of the core material.  In the treble, I had observed that the counterbearing surfaces seemed to be ground down from a previous restringing, so I prepared brass inserts to restore sufficient deflection angles at the capo.  Once I began to string, however, it turned out that the deflection angles were fine, so the brass inserts were set aside.  I am pleased with the rendering of the system.

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    Floyd Gadd
    Regina SK
    306-502-9103
    ------------------------------