I have read with interest the comments on threading.  Basically there
are two types of ways to put threads on steel.

1. Cutting threads

You can use a round die that you find in tons of sales outlets.  These
actually cut away some of the metal leaving a thread.  Theses threads
are usually the same outside diameter as the piece on metal.  This
method is usually done in home shops.

2. Rolling threads

The second method uses several dies that rotate around the metal but
they don't cut threads as they press the metal into threads.  These
threads are slightly larger in diameter than the original piece of
metal.  The equipment to form these threads is very expensive but the
threading is very fast.  These threads are known as rolled threads and
have been used by industry for years.

I can't think of any thread in a player piano that is a cut thread.
I feel hundred percent sure that the threads on the eye screw recently
mentioned in MMD would have been rolled.

I have been wanting a thread rolling machine for several years but the
cost for a small shop like mine has prohibited me from obtaining a
decent machine.  One tool mentioned for bicycle spokes made cut threads
but there is one available for about thirty four hundred dollars for
rolling threads.  There are some thread rollers that work in a metal
lathe for around two thousand dollars.

Don Teach
Shreveport, Louisiana