How much hammer shaping do I need to do?

Question

I am repairing a piano for my Church. It is an older upright, with no identifying logos whatsoever. I'm assuming they were lost in a previous refinishing job. Several hammer heads are missing, so I have taken replacements from an older Burroughs upright. I took them from the same notes as my missing ones, but some of the Burroughs heads are larger than their new neighbors. In order to get a consistant sound up and down the keyboard, do I need to file them down to the smaller size? I need to reshape them anyway, as they are grooved. I just want to know if the larger size will have an impact on tone quality. Thanks for your time.

Money is an issue for the Church, that's why I'm recycling parts and donating labor.

Answer 1

The sound is not going to be consistent to begin with because the heads from the other piano are of a different weight, material and made by a different manufacturer. And being that you have to reshape the surface so that the grooves will line up with the strings, you are essentially changing the performance quality of the head. You are better off installing the heads as-is. If you attempt to make the heads appear to be the same as the original ones, it might LOOK nice inside of the piano but it might sound very different. Depending on the difficulty of what needs to be done, I think I would take my chances of the heads sounding slightly different in their unmodified state than to attempt to change them, thus, making them sound VERY different.

Answer 2

Personally, I would reshape them just enough to lose the grooves. I'd install them and check the relative action weight after that. I'd be more worried about an action inconsistancy than a voicing inconsistancy. You can always voice the hammers later.

Answer 3

yes they will because they will make a louder noise.