<HTML> <HEAD> <TITLE>Re: [CAUT] stack fit to keyframe</TITLE> </HEAD> <BODY> Hi John,     Quite right. I should have added “in current production.” Ron Overs is the first to point out that Herrberger “went there first” in regards to knuckle/jack being on the convergence line. Ron’s action has several additional features.     BTW, I like that felt on the jack tender, rather than on the letoff button. Prohibitively expensive to make, but a nice feature, IMO.     Thanks for sharing the illustration. Regards, Fred Sturm University of New Mexico On 9/12/06 5:28 PM, "John Delacour" <JD@Pianomaker.co.uk> wrote: <BLOCKQUOTE>At 3:57 pm -0600 12/9/06, Fred Sturm wrote: <BLOCKQUOTE>The major friction in the action, though, is knuckle to jack/rep top, which is far from the convergence point except in Overs' design. </BLOCKQUOTE> Strictly not so.  Here is Herrburger's action from 1898, which was imitated with variations but no improvement by one or two other action makers.  Note that the two arcs are as near to touching as can be throughout the descent of the hammer into check. JD <IMG src="cid:3241011701_1919736" > </BLOCKQUOTE> </BODY> </HTML>