A lot of variables here. As Bill mentioned you can usually tell if the hammers have been changed (if the shanks are still original) by looking at the back of the hammer where the shank protrudes. But it may not matter.
First a careful check of the string mating should be done first and I would probably give them a very light filing first. Moreover make sure that the prevoicing routine is covered and you can save yourself some wild goose chasing.
The first goal is impedance matching. You want the hammer to deliver only as much energy as the board can handle without getting too percussive or harsh. Older, more reactive boards will require softer hammers, generally, because they tend to produce a stronger more percussive attack and reduced sustain. The impedance matching phase is to balance the energy delivered from the hammer with what the board can handle. So you want to be testing with firm blows and then try and determine where the hammer is too hard before you just start stabbing. If you can easily sink a three needle tool into the shoulder of the hammer (I use the standard routing--not from the side) then the hardness is likely located more directly under the crown. You can work toward the crown with the three needle tool turned 90 degrees so only one needle is really contacting the hammer and work toward the strike point. Angle the needles away from the crown so you preserve an upside down triangle (point up) under the crown that is mostly untouched, at least at first. You can insert the needles on the strike point directly if they are angled out like that avoiding the area directly underneath. Work carefully with a hammer or two in each section to see how the hammers react and trying to target a sample in each section which you can review with the customer to determine their preference for level. Keep a mental note of how many insertions and where. Work one section at a time (I usually start in the temperament area and work out, toward the treble first). Again, these are relatively firm blows you are testing, trying to create some uniformity at mf - f levels. After that you can work the crown with a single needle tool to reduce the attack for pp - mp or a multi needle tool (6-7 needles protruding 2-3 mm from a handmade dowel tool that I have).
The second goal is that the tone should get progressively louder and brighter as you increase the force of the blow. A hammer that still has some resilience (i.e., it springs back quickly to its original shape after compression) will accomplish that. The faster the hammer springs back, the faster it gets off the string, the brighter the sound, all other things being equal, because of less internal damping. If the hammer lacks resilience then you won't get as progressive a development in timbre. Harder blows will get louder but not necessarily brighter. You often see this on lacquered hammers where the the hammer has little resilience, or restitution capacity. You also see that in hammers with dead felt either from age or over needling. Those hammers tend to be less stable as well. If the hammers are original then the spring in the felt is likely gone as the tension in the felt will have dissipated. If they are 50 years old that also may be the case and depending on what was put on you may have more or less success in this area.
If the hammers are original then the Weber hammers are an american felt hammer with a not very firm pressing. It's not likely that a lot of shoulder needing will be necessary. Once the shoulders are open either by manufacturing process or previous needling you don't usually need to revisit that area, with some exceptions. But, as I mentioned, they are probably somewhat dead at this point anyway. You will be lucky to simply created a gradient of density that will render them at least acceptable though not likely that stable.
The third goal is to balance the levels from bass to treble so that the treble speaks through the bass and the bass has adequate power without drowning out the treble. Along with that you will also establish a smooth progression from bass to treble. A dead treble section because of the soundboard will create some challenges and you will have to make a decision as to what your priorities are. In these cases I usually focus on the center of the piano to make it as nice as possible and then blend the upper and lower sections as well as I can. Generally, lighter hammers in the treble on old boards are better, in fact lighter and softer hammers work better on older soundboards most of the time for reasons given in goal number one: impedance matching.
There's really no direct advice that you can be given on a specific piano because the interplay between the hammer and soundboard determines so much of what you can or can't do that you just have to experiment and be judicious and methodical in your approach.
Oh, you can get an acceptable even charming result with alcohol or vodka but I prefer more direct contact with the hammer using needles.
Good luck.
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David Love RPT
www.davidlovepianos.comdavidlovepianos@comcast.net415 407 8320
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Original Message:
Sent: 09-11-2017 22:18
From: Geoff Sykes
Subject: Voicing question #1
Customer has a 1918 Weber baby grand. Purchased used from a store, by her father as a gift to her, about 50 years ago. Was played lightly for a couple of years and then went essentially untouched until about a year ago when she started taking lessons. What I have found is that the regulation is quite good and the hammers were obviously reshaped with some skill prior to sale. Had to twist the bass strings to wake them up and today I had to Teflon lube the knuckles to help with uneven touch. Only thing left, now, is some voicing.
The hammers may not be original, no way to know, but they are definitely over 50 years old. Only slight and shallow grooves since it has not been played. Piano sounds very harsh and bright.
Question: Prior to needling, can hammer felt that is this old be helped with some light filing/sanding to get rid of the old exposed layer and expose some, theoretically, "newer" felt underneath? Or, am I going to find that an old hammer like this is going to be old and hard all the way through?
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Geoff Sykes, RPT
Los Angeles CA
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