Action Ratio, was: More off the wall stuff

[Farrell]

So is it not best to simply measure how many units of hammer rise you get for each unit of key depression? I have two little blocks that slip under the key front. They have 5 mm difference in height. The taller one will meet the key with just a slight key movement (to avoid any funky stuff right at the immediate start of key/action movement, and the shorter one will meet the key before letoff. Place the taller block under the key front and depress key to meet block. At that point you measure the height of the hammer. Then you place the shorter block under the key and depress the key the additional 5 mm that the shorter block will allow. Again measure hammer height. The blocks allow a very precise 5 mm (or whatever you want to use) keystroke. You should be able to measure hammer height pretty accurately.

Is the convention to measure key height at the very front tip?

Seems to me this approach will eliminate any questions about exactly where to measure, etc. Does anyone see any shortcomings with this method?

Terry Farrell
  
----- Original Message ----- 
From: "Overs Pianos" <sec@overspianos.com.au>
To: "Pianotech" <pianotech@ptg.org>
Sent: Saturday, January 18, 2003 12:36 AM
Subject: Re: More off the wall stuff


SNIP

> ......  At the end of this process, no matter which way 
> you measure the ratio, we are all primarily interested in how many mm 
> the hammer strike point moves for each mm of key dip. 

SNIP
 
> Ron O.