Damon 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.

Part of your problem is that it's not a "bolt", it's a "pin".  I can
imagine a "nuts and bolts" clerk not knowing what a "pin" is unless
you threw it at him. :)

It sounds like what you want is a "grooved clevis pin with retaining
ring", which you can get from McMaster-Carr in 18-8 stainless steel,
which is a good (visual) match for nickel plate, so it will even look
'period'.  You'll find the pins mentioned above on page 2753 of the
McMaster-Carr on-line catalog at

    http://www.mcmaster-carr.com/

If the holes in your linkages have worn out of round, you should bore
them out oversize to get a nice, circular hole, and then press a bronze
bushing into the hole.  This will wear much better than steel against
steel, and when the bushing wears out in a few decades, knock it out
and pop in a new one.

You'll need a sturdy drill press with a rock-solid vise to do the
boring, though.  Otherwise the drill bit will wobble around and you'll
just get a larger version of the old ugly hole.

regards,

Colin Hinz
Toronto, Canada