<html> <body> Thanks to all who have responded to this. UMass is on winter break until a week from Monday and after that I'll have a chance to get back to that piano (private customer). In response to what I've read so far: I will of course recheck the regulation, but I don't think that's the issue. The bobbling happens on a very soft blow when, I suspect, the key doesn't ever go all the way down, so more key dip won't help. I'll check the profile of the butt "leather" to see if a thicker butt felt will allow better escapement without allowing the jack to skip out too easily. To go back to why I landed on pinning and return springs as a solution: On a very soft, incomplete, blow the hammer is thrown at the string just as the jack hits let-off. The hammer then rebounds from the string but since the key has not been fully depressed when the hammer rebounds from the string (as someone said, it could be .005" short of complete travel and that could make the difference) it hits the jack and rebounds off of it. If there is no resistance in the pinning, and the hammer springs are weak, it will just bounce off the jack, back onto the string, back onto the jack, back onto the string, until it runs out of energy. There was one part of my question no one answered. That was about good quality flange bushing cloth. I haven't had to buy any for quite a while so I was wondering about a good source. Also, since we had the discussion about glues; does anyone use anything but hot hide glue for rebushing flanges? And just a bit off topic: My email program (Eudora) monitors incoming mail for questionable or just plain foul language, and alerts me by marking such incoming mail with one or more chili pepper icons in my inbox. Several of the posts on this topic arrived with "chilis" and it took me a while to figure that the program didn't like all this talk of "butts". I'm also looking forward to checking out Don's info on the sticker tongue position. (Butts and tongues--what is this list coming to?) Aaron <blockquote type=cite class=cite cite=""> <blockquote type=cite class=cite cite="">There is a Mason & Hamlin upright model 50 (vintage 1975) I service and at the last tuning the owner was complaining about bobbling hammers. The hammer pinning is very loose. I played around with the note that was bothering her the most and through a combination of repinning and strengthening the hammer return spring was able to all but eliminate the problem. The piano is in good regulation. Here's the issue: The action is really poorly made. 1975 was not exactly the golden age for these. In repinning the one I did, I could see that the flange bushing cloth was poor quality. It would be wonderful to replace the whole action, but that's not going to happen. Does anyone know if it's possible to get replacement hammer flanges? These flanges are different from the generic ones sold by piano supply houses. If that's not possible, I have to go with rebushing what's there. Any recommendations on a good source of flange bushing cloth? I know M&H are making these again. Anyone know if the action design is the same? thanks, Aaron ------------------------------------------ Aaron Bousel Registered Piano Technician, Piano Technicians Guild <a href="mailto:abousel@comcast.net">abousel@comcast.net</a> (413) 253-3846 (voice & fax) </blockquote></blockquote> <x-sigsep></x-sigsep> ------------------------------------------ Aaron Bousel Registered Piano Technician, Piano Technicians Guild abousel@comcast.net (413) 253-3846 (voice & fax)</body> </html>