replacing a back action on a 1909 Steinway B

[Jon Page]

Dave made a few good points for replacement of the back action.
Another is to replace the older version without the brass set screw
bushing because the wood is fragile and will not hold the screw tightly
or simply cracks. One could install these inserts but another reason
is to replace the old stiff sostenuto tabs with the spring-loaded tab version.

I also take the opportunity to move the tray pivot to be in line with the
flange centers. This is accomplished by holding the end block and a flange
to the rail and tapping the pin with a hammer to dimple the block.
This makes the pedal lift the same motion as the key lift
and there is no discrepancy with setting the upstop rail.

I also set the pivot height such that the key lifts the underlever to 
a position
parallel to the key bed. A pivot which is too high has the underlever at too
steep of an angle and digs into the lifter felt causing drag and wearing
a trench (which Dave mentioned). Reducing the lifting friction makes the
action play more smoothly. Lifting beyond parallel is counter productive too.
Lifting to parallel induces the least friction.

Sometimes you can not change the back action as it happened recently
on an 1884 Chickering grand.  The wood was deteriorated enough not
to hold the threaded wires securely, so I installed the brass inserts.
Fortunately there was no sos. to contend with.
-- 

Regards,

Jon Page