Thanks, Kevin and David. I've taken Oorebeek's class, and he focuses mostly on preparing brand-new hammers (while these techniques should work on old hammers somewhat).
It's interesting to contrast the two answers: one is to harden the staple area to support the crown, and the other is to soften the staple area to allow tension to move up to the crown. Standard shoulder needling should reduce string contact time and increase power, too. I've done the binder clip trick on uprights, but hadn't thought about it for grands. The hammers are rather small overall; haven't measured weight.
Kevin, you gave one specific answer I was looking for: how effective one technique is over another. With a given time budget on a piano, I'm looking for a technique that's less time-consuming than deep-needling half of each hammer. I'm also guessing this is less effective on 30-year-old felt than on new felt.
And what about resurfacing the strike point? No one has chimed in with a vote for that approach.
I'm leaning toward a combined approach: lacquer for a big win, and then needling to even it out.
--Cy
------Original Message------
Cy, Here is what I would probably try BEFORE breaking out the hammer stiffener/hardener- at least on a couple of hammers to see what it will do.( It may also help David's lacquer technique work even better if in fact it is still needed. --although David's post is very good, especially the binder clip trick.)
I have attached a pic of a hammer that is labeled according to the particular voicing areas, so that we can all see what we are talking about. First I would do some deep needling low in the shoulder (area 5--maybe about 5 to 7 insertions with the 3 needles, about 1/2 inch deep. Then work your way up to about 3 and 9 o'clock--probably just above, using the same technique. It may take a fairly large number of insertions in area 4, but you can just see what effect it is having and do a little more, etc--before you make a final decision. What this will do is release the tension from what Andre' Oorebeek refers to as the "battery" or "reserve power" area (area 5 in pic---see "the Voice of the Piano by Oorebeek), ALLOWING the tension and power to move up the hammer more toward the strike point, greatly increasing the power and dynamic range, etc.
From Craig Waldrop at Baylor I have found to be true): "Deep needling directly into the 3:00 and 9:00 areas (area 4) WILL increase power. It takes more needling in this area to be effective as it is less sensitive, but it works!"
Hope this helps someone, if nothing else.
Also
I had to do this on a set of Abel Naturals I just installed on a Baldwin L.- they were NEARLY in the "Q-tip" range on this piano.
I installed another set of Naturals last month on a Steinway L and they were nearly perfect, just had to open up the shoulders a little mainly.
(I tried a set of Pianotek's "special press" on the same Steinway L first, but they were WAY too bright for this piano prof. It seems to me the "special Press hammers are quite a bit harder than the Naturals--right out of the box. Just my limited experience so far.)
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Kevin Fortenberry
Registered Piano Technician
Texas Tech University
806-778-3962
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Original Message:
Sent: 09-12-2014 17:47
From: David Andersen
Subject: Adding power and tone
Hi, Cy---I have had great results many times with hammers such as you describe by treating the lower half of the hammer---from the start of the felt to 3 and 9 o'clock on the shoulders---with 6:1 acetone/lacquer solution. Wait a day, and I speculate magic will happen.
Also, if the action has a low balance weight (DW+UW /2) you can add a .5gm mini-binder clip to the shank as close to the hammer molding as possible. This will add power and fundamental tone.
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David Andersen
Los Angeles CA
310-391-4360
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