Recently I was asked to help disperse the shop of a local gentleman,
some ten years deceased, a player and reproducing piano rebuilder of
amateur status, i.e., not professional; however I have no knowledge
of the quality of his work.  Among the usual tools and materials was
a home-made jig whose purpose I have been unable to discern.

It consists of several layers of machined aluminum with a field of
36 rectangular holes, each measuring 0.125" x 0.250" x 0.565" deep,
and spaced according to the attached photos.  It seems to be really
over-engineered.

Some of the holes have some impingement damage around their top edges
as if they were used as a female "die", being used with a matching male
"punch".  However, aluminum is not a very good choice for this kind of
operation, and no "punches" were found among the effects.

Each "layer" was stamped to insure proper re-assembly if taken apart,
which would have been a non-trivial task given the number of screws
and nuts.  I cannot say with certainty whether this jig would have
served a piano-only task, or a player task which is not apparent to me.
What say you?

John Grant

 [ http://www.mmdigest.com/Attachments/17/05/20/170520_144223_Mystery_Jig_1.jpg 
 [ http://www.mmdigest.com/Attachments/17/05/20/170520_144223_Mystery_Jig_2.jpg 
 [ http://www.mmdigest.com/Attachments/17/05/20/170520_144223_Mystery_Jig_3.jpg