wrote in rec.crafts.textiles.sewing:
Followup:

http://www.sears.com/partsdirect

enter part number 26071 in the part number box to get the instruction
book for your Sears Kenmore model 1750 / 2142 and possibly other
models
of sewing machine.

Yours,

Doug Goncz
Replikon Research
Seven Corners, VA 22044-0394

Now that I looked in the right place, I realize my sewing machine is
model 158.17501 and the _motor_ is model 2142.

The rubber tire for the bobbin winder came from Sears, and it fits. It
is a standard rubber O-ring, marked 15287 A.

Can any of you metalworking types identify a standard O-ring that bears
this marking? It's pretty close to 5/8 x 1/4 x 1 1/8, a little
oversized.

Yours,

Doug Goncz
Replikon Research
Falls Church, VA 22044-0394