Back in the seventies, when I was just gathering steam, the general rule for historically challenged harpsichords was 2 grams needed to gey the lower manual keys to move forward without any jacks. The upper manual keys stayed rested only by an unseen force and one's hot breath was enough to make them depress. This was discribed by some as the "classic french touch" and those of us who went on to study antiques in museums found that a whole lot of keyboards were out of these strict boundaries. Tra-La!. Key plank materals, plating thicknesses and stock all effect the balance' 
My rule now is that the keys must have a non variabe resting place so that they can be set level and then you add the weight of the jacks and the pluck. One can gain lots of valuable experience from working on clavichords which display every quirk in the barrel. Tangents are nevr heavy enough by thrmselves in the trebls where keys shanks can get as thin as 3mm AND you've carved out under the head so as to make the playing surface almost transparent. These are all things we folks get into almost daily! The very light touch instruments I've made are hard to play and unrewarding as to feel. If you don't want any sense of key then play the harp! Jack Peters 
----- Original Message ----- 
From: "Peter Redstone" <[log in to unmask]> 
To: [log in to unmask] 
Sent: Sunday, November 7, 2010 11:23:00 AM 
Subject: Re: key balance 

Hi folks! Michael Johnson wrote: 
> 
> Firstly in order to get the fulcrum working properly you must have the 
> minimum of friction at that point and indeed all the other locating 
> points at the back or front end of the key.I say front because Peter 
> will say his instruments have a front pin or bat, mine work from a 
> back pin and rack. 
> 
Michael! Michael! What are you accusing me of???? Bat pins? Those 
things are late piano pins, and are for much thicker keys too. Next 
you'll be accusing me of using cloth bushings at my balance pins! 

The majority of my instruments (the earlier ones) have a rack at the 
back, with a thin wire between the key-ends or a slot in the end of the 
key for the wire. The thin wires need an over-rail since they aren't 
stiff enough unsupported. The wire I use is tinned 1/16" brazing rod. 

The few late instruments I have made, after Shudi and Kirckman came on 
the scene, use front guide pins which are the same material as the 
balance pins: 3/32" brazing rod, tinned the way Hubbard described, using 
tin filings and cream of tartar. 

A lot of English keyboards need lead weights. In the old instruments, 
generally two thicknesses of 1/8" sheet lead in a chiselled mortise 
about 1/2" to 3/4"long were used. The keys are of pine, not very thick 
(some under 1/2") which, not being anywhere near as heavy as 
lime/basswood keys, means that the ebony keyplates (and solid bone 
sharps) inevitably make the keys front-heavy. Hence the lead weights. 
QED! The leads are positioned so as to make the keys barely tail-heavy. 

Best! 

PR 

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Note:  opinions  expressed on HPSCHD-L are those of the  individual con-
tributors and not necessarily  those of the list owners  nor of the Uni-
versity of Iowa.  For a brief  summary of list  commands, send mail to
[log in to unmask]  saying  HELP .
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