Hammer Felt

[Stephen Birkett]

Phil wrote a very good post about felt:
>       And in a previous post I was trying to convey the idea that the
>makeup of the felt itself is important ....

Also the point I was making, which is why we have been studying the 
compression properties of (different types of) felt independently of 
piano hammers. We can't hope to understand the effects of 
hammer-making operations until we know a bunch about the felt 
material they're made from.

>   Can you imagine anyone in the world being willing or able to supply such a
>thing in 2004?  Forget it.  In 1904, probably.  But we've made 100 years of
>'progress' since then.

Well I can actually imagine it in 2004. There is clearly a market, 
albeit a niche one, and an available product that could fill that 
need would probably sell. I think the problem is missing knowledge: 
(a) we don't really know what properties of felt are desirable for 
hammer-making; (b) we can't quantify those properties; (c) we don't 
have ranges or desirable targets for those properties; (d) we don't 
know how the raw material (wool type) relates to the finished felt 
product properties; (e) we don't know the relationship between the 
processes used in felt manufacture and the mechanical properties of 
the finished product. In other words, lots of don't-knows, and 
consequently much speculation. We've come some of the way to 
answering (b), and have hints about (a), that after several months of 
experimentation.

By the way, a traditional way to full felt was rolling it up in a 
cloth and and roping it onto the back of your horse all 
day....pressure from trampling, heat and liquid from other obvious 
sources, all the essential components.

Stephen

-- 
Dr Stephen Birkett
Associate Professor
Department of Systems Design Engineering
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1

E3 Room 3158
tel: 519-888-4567 Ext. 3792
fax: 519-746-4791
PianoTech Lab Room E3-3160 Ext. 7115
mailto: sbirkett[at]real.uwaterloo.ca
http://real.uwaterloo.ca/~sbirkett