Hammer leather

[D.L. Bullock]

I would be interested in the experimental leather you are working on.  I
wonder if there is a way to use chromium in order to leave 4% chromium salts
in the leather to prevent it from turning to powder within 12 years.

The organ historical society found that chrome tanned leather lasts 50 years
or more.  It is now universally used in pipe organs and pneumatic player
systems.  The only drawback to pipe organ and player piano restorers is that
the chromium tanning process makes the leather more porous and more
flexible.  However I have seen one great valve leather that  was vegetable
tanned for the airtight quality and then tanned again with chrome.  This
leather was totally airtight and is impossible to find now in the US.  The
company who makes it is Felix Trading in Australia.  Their US distributors
are Schaff and Organ Supply Industries neither of which knew what I was
talking about when I tried to order it.  It was thick and firm but flexible
and would probably be perfect for hammers.  It acted most like vegetable
tanned leather we used to use thirty years ago.

I have recovered hammers on square Chickering pianos and have gotten great
tone with little flop.  Of course I layered them up exactly like the
originals with glue only going as far as the original did.  Each layer was
skived to shape it.  The center core was a large half circle of Hard 3/8"
thick leather glued to the end of the wooden molding.  Each layer was
stretched tightly as they were glued up.  This technique made for firm
shoulders and a tone very close to a good set of felt hammers but with a
distinct difference.  Unfortunately, I could not get the Australian leather
so I used the best chrome leather I could find which most approximated the
original leather.

If you need to know how to find out whether your leather is vegetable,
chromium, or alum tanned, I can tell you how to test it.

D.L. Bullock
www.thepianoworld.com
St. Louis