Touchweight

[David C. Stanwood]

>Hi, David,
>
>You "recommend that any tech who is replacing parts learn how to use a
>standardized method of measuring key weight ratios or key distance
>ratios and keeping notes on what key ratio works best with which part
>and hammer weight level."  Any particular method in mind?
>
>Paul S. Larudee, RPT
>Richmond, CA

Hi Paul!

Yes I recommend using Key Weight Ratio as described in the June 1996 "The
New Touchweight Metrology".   But with some refinement...  

The article describes tipping a key on a scale and holding the front of the
key down with a 70gram weight.  The scale is tared to zero then a 100 gram
weight is placed PRECISELY over the capstan contact point.  The scale
reading tells how the weight was transformed through the key.  

For instance: a reading of -58.8 would meand a key ratio of 0.59.

Some refinements to the technique are as follows:

The key now set on the scale using a bubble level so it sets level on the jig.
This makes for better repeatability.

We now use a 10gram weight centered at the capstan. (two nickels on either
side works sometimes).   This gives a reading that is already rounded off
to two places for instance in the above example the reading would be -5.9
wich means a key ratio of 0.59.  It also means you don't have to use a
weight to hold the key down because the 10 grams is so much lighter than 100.

We don't use distance measures because it's touch "Weight".

The method is really fast too!


David