Heintzman console jack return problem.

[Joseph Alkana]

Douglasmahard@AOL.COM wrote:
> 
> Hi all,
> 
> Heintzman console with jacks not fully returning under hammer butt.  The keys
> are weighted/balanced such that the lost motion is taken up on most keys.  On
> my experimentation key (middle C) I added a key weight which allowed me to
> feel the lost motion, but the jack still would not return when letting the
> key rise slowly.  Next I installed a new jack spring with no improvement of
> jack return.  I also checked the profile of the butt leather and it looked OK
> to me.  Graphited the top of the jack also.
> 
> I would appreciate any insight.
> 
> Thanks and have a great weekend.
> 
> Doug Mahard


Doug,
I don't claim to be an expert, but I'd like to share some observations.
First, I think it's a mistake to assume that the keys are weighted to
take up the slack to eliminate lost motion. On a vertical piano you
should be able to accomplish reduction of lost motion in other ways,
i.e., by proper adjustment of the capstan. Weighting, then, is more a
function of balancing the action to function within narrow timing
parameters of key return and repetition considerations. On troublesome
verticals I often find the factory weighting, or lack thereof,
problematic and have found back weighting (behind the balance rail) many
times beneficial.
It seems to me that other areas bear looking at for poor jack return.
The list is long but don't overlook key bushings as a potential trouble
spot. look for "dents" in the bushing cloth, especially on those dogleg
keys. Then the usual friction sources such as rubbing keys, tight key
bushings, tight balance rail hole, tight action centers in the whipen or
hammer or jack assemblies. 
Next I'd move on to regulation flags, such as jack rotation showing up
as too much clearance between the hammer butt and the jack at full key
dip. Usually going carefully over the steps of regulation such as those
listed in the PTG handbook "Piano Action Handbook" compiled by Randy
Potter will show up problem areas. 
Hope this helps.
Joseph Alkana