hammer repair w/leather

Stephen Birkett sbirkett@real.uwaterloo.ca
Mon, 08 Jul 2002 02:12:16 -0400


Tom asked:
>So what kind of letter [leather] is used to cover a hammer which has worn 
>through the
>felt to the wood?
>Backcheck leather, maybe?
>And what kind of glue?

Hammer leather aint no more unfortunately. The proper stuff was a 
specialized product even in the 19th century and required a special recipe 
and processing to achieve the required physical properties. There is simply 
no leather now made that is anything like hammer leather was and needs to 
be. That may change soon if a little project is successful - more on that 
later.

So - whatever you use (and that includes for hammers that are layered 
leather, as in early 19th Century pianos.) is a compromise.

joe wrote:
>....is quite acceptable for your average "clunker". Of course, the client 
>needs
>to be informed that this is merely a stop-gap until new hammers can be
>installed.

Well, according to Carl Kuetzing (The Science of fortpeiao building and 
design, Bern, 1844) "if felt is used as an underlayer, and then covered 
with leather, it is in the right place and in that way there can be a 
saving of some leather, but it should definitely not be used as the 
'intoning' material". He continues that "felt is not durable enough as the 
strings cut into the felt". At the time, most (Viennese and other) pianos 
had an outer hammer layer of leather over felt. Keutzig's explanation 
shows  that they regarded the felt as a quick substitute for a mass of 
leather (more difficult), but the outer leather was still regarded as 
important for: (1) durability; and (2) tone. Funny how attitudes changed 
and we ended up with all-felt hammers when them lazy builders simply left 
off the outer leather.

Can't see any reason to apologize for an outer leather layer on a modern 
piano if it sounds good - except it probably won't because you can't get 
the proper hammer leather now, and what you can get probably will start 
flapping about after a bit of playing....

Stephen

Stephen Birkett Fortepianos
Authentic Reproductions of 18th and 19th Century Pianos
464 Winchester Drive
Waterloo, Ontario
Canada N2T 1K5
tel: 519-885-2228
mailto: sbirkett@real.uwaterloo.ca
http://real.uwaterloo.ca/~sbirkett



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