Key Bushing Clearance/Friction, was: Key mortise correction

[Ric Brekne]

Hi Terry

You dont really.  0.002" and 0.005 are rather more like of theoretical 
values which ends up being very close to what the <<optimalized>> 
bushing feels like.  You develop a feel for this sideways motion in both 
the keybutton and the front bushings.  And... as such things go... the 
actual results vary a bit from tech to tech.  Experienced techs whov'e 
gotten good at this however display a pretty high degree of likeness in 
end results.

As for how much friction this ends up yeilding.  Total key friction 
shouldnt end up being more then absolute max 2 grams IMB... and I strive 
for 1-1.5 grams.  I find it difficult to understand how you can 
consistantly get lower then this and still maintain firmness of play myself.

Cheers
RicB

---------
Two questions: How do you go about measuring key bushing clearance? And 
how much key friction does these specs commonly yield?

Terry Farrell
  ----- Original Message -----
  SNIP
  4. Tight key bushing's.  Gently squeeze the bushing to have .002" 
clearance at BR bushings and .005" for FR bushing's.

  Regards Roger