Regulating A Square Grand

[Joe Garrett]

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Patrick C. Poulson said: "Hello All: I have taken a square grand action =
into the shop to regulate, and=20
am stumped as to how to efficiently regulate lost motion. In particular, =
how=20
does one get to the rocker capstan screw that is underneat the hammer =
rest=20
rail? My offset screwdriver doen's fit in there very easily, and a =
straight=20
screwdriver doens't work very well eithere. Anybody have a suggestion? "
Thanks,
Patrick ,
First of all, you cannot Regulate a Square Grand on the Bench! It must =
be done in the piano! However, while you have the action in the shop, =
(hopefully doing some reconditioning<G>), there is one thing that can be =
done to gain access to the Rocker Capstan Screws: draw pencil lines on =
the "let-off rail" that show the hammer shank positions in juxtaposition =
with this rail. Draw "cross hairs" that show the position of the rear =
capstan screw(s) on the rail, as well. Remove the "let-off rail" and =
lightly center punch the "cross hairs" for each note. Take it to your =
drill press and drill 1/4" holes through the rail, for each note. A =
slight counter-sink, on both sides of the hole is a good idea also. =
Clean up the splinters. Reinstall the rail on the action frame. Now you =
can access the screws for the Rocker Capstans. I use a long screwdriver =
w/the tip slightly rounded, (you'll see why, when you start =
adjusting<G>) One caution: YOU MUST HAVE LOST MOTION! (just like in =
spinet PSOs) This is difficult to do, as the action frame is VERY =
flexible and will conform to your bench top, which is in no way like the =
key bed! (Yikes!<G>) The final adjusting MUST be done IN the piano! Lots =
of  IN/OUT is needed. Use the Handle All The Time!!! (else, your hands =
will inadvertantly hit a key, which will cause the hammer to go up and =
catch on the underside of the soundboard, etc., causing a broken =
hammer!!!!!! Use a "code" with chalk, to tell you how much/little lost =
motion/let-off/checking is needed, so you reduce the number of times you =
have to "pull" the action. The last thing you do, is set the =
dip/after-touch. BTW, do all of this with the NameBoard removed. When =
you have accomplished all of this, Then, put the Nameboard back on. =
Phew! (It's so much easier to show, rather than tell how all this is =
done!)
OOPS! While the action is on the bench, make sure you adjust all of the =
hammer flange pinning! A very light touch with a regulating screw driver =
is needed. Raise the hammer/shank to string height and drop it. It =
should do two bounces. If it does more, the flange is too loose. If it =
does less, the flange is too tight. If you are doing key bushings, you =
MUST ease the keys for very loose, (but not sloppy!). Back checks need =
to be aligned and set approx. 1/16" clearance with the tails. Iguess =
that about covers it. If you run into problems....call me.
Best Regards AND Good Luck!<G>
Joe Garrett, R.P.T.
Captain, Tool Police
Squares R I
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