Hi Alan - I think any confusion is related to my unconventional friction measurement at the hammerhead. I only did that as a way to measure friction while installed on the hammer rail. The 5 - 10g friction was at the hammerhead (just as you describe) forward and backwards (yes, with the spring engaged - hence the difference in forward friction vs backward friction). The 1 - 2g friction was again at the hammerhead (with the hammerhead upwards like it is when mounted on the rail) while holding the flange in my finger. For sure, the actual numbers represent a somewhat meaningless friction measurement, but it does demonstrate the
difference in friction when the hammer assembly is mounted on the rail vs unmounted. I can measure the friction at the hammer both ways, but I can't measure the friction at the flange when it is screwed to the rail - only when it is unmounted.
Does that make sense?
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Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com813-684-3505
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Original Message:
Sent: 06-13-2022 13:24
From: Alan Eder
Subject: Hammer Butt Flange Friction Mystery
Terry,
Please help me understand a couple of things.
When you say that you, "Check friction at hammer front and back and it is 5 to 10 grams when on rail," do you mean using a gram resistance gauge to push the hammer forward from the tail, and push it back from the hammer crown, presumably without the hammer return spring or bridle tape engaged? Might the acton be mounted on LaRoy's action cradle, and inverted such that the shanks are hanging vertically?
Also, did you ever figure out why, after you removed the parts from the rail, the resistance that was originally 3-5 grams had dropped to 1-2 grams? My apologies in advance if you already covered these points and I somehow missed it.
Thanks,
Alan
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Alan Eder
Valencia CA
Original Message:
Sent: 06-12-2022 17:05
From: Terrence Farrell
Subject: Hammer Butt Flange Friction Mystery
My measuring methods, I think, are reasonably described in my post. However, the problem as been solved. The problem only manifested itself in the treble section. The tenor and bass were nice and free. The flanges have some space between them in the tenor and bass. In the treble they are jammed snugly against one another. I removed a couple butts and inspected the pinning and bushings. Both protruded from the side of the wooden flange a small amount. I pushed the pins out a hair and cut is a tiny bit shorter and sliced off any protruding bushing. Reinstalled the trimmed assemblies and all if fine. Hammers move freely.
What a weird thing - I had just never seen that sort of a thing happen before! The center pins that stuck out a hair (and I mean a HAIR), were rubbing on their neighbors and creating excess friction!
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Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505
Original Message:
Sent: 06-12-2022 16:17
From: Peter Grey
Subject: Hammer Butt Flange Friction Mystery
Terry,
How are you measuring it in the piano?
Peter Grey Piano Doctor
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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 06-12-2022 15:52
From: Terrence Farrell
Subject: Hammer Butt Flange Friction Mystery
Working on a Yamaha console (yes, same one....). I replaced all the butt spring cords and repined all the flanges. Checked all the flanges for friction and all were 3 to 5 grams. Install the hammer/butt/flange assemblies onto action rail and flange friction is excessive. Check friction at hammer front and back and it is 5 to 10 grams when on rail. Take butt assembly off rail and check same hammer front and back friction values and it is 1 to 2 grams. Put back on rail and it jumps to 5 to 10 grams. Many are like that. I've not ever seen this happen before. Any thoughts? I don't see that anything is binding anywhere.
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Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505
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