I have heard of horn being used for guide slips but not as key-covering
material, though I think it would be hard enough. Perhaps it is just be
too difficult to get pieces wide enough for naturals. Also, the appearance
would be somewhat... rustic.
Peter Bavington
Harpsichord and Clavichord Maker
291 Sprowston Mews
London E7 9AE
England
Tel and fax: +44 (0)20 8519 1170
e-mail: [log in to unmask]http://www.bavington.nildram.co.uk