Damon Atchison wrote:

> I have a bolt which is in the joint of the bellows pedal assembly.
> It's almost like any other bolt, but it has no threading, the head is
> thinner (flatter), and there is a small notch near the top.

The device you mention is a bolt furnished by bushing and bearing
suppliers.  In the modern incarnation it is a flat-head threadless bolt
with a spring clip through a hole at the opposite end.

The original usually had a cotter pin through it.  You may have to
drill out the holes in the arms and insert a new bushing to prevent
the noisy slop of an oval shaped hole.  I have a box of these items.
I shall look at the box and see what they are called and let you know.

D. L. Bullock    Piano World    St. Louis