On Jul 6, 3:27*pm, "justme" wrote:
Folks, I am wanting to couple a square shaft (~.310inches) to a pulley of ~
2 to 4 inches in diameter with ~ .500 or .625 hole for the drive of this
pulley.
If I can't do that, I guess that I will have to butt the shaft up to a motor
whereby the motor's shaft will be round.
jb

A two-piece split adapter should be easy to make. Set the stock at a
45 degree angle to mill the vee grooves, cut down the mating surfaces
until they almost meet, drill and tap for two clamp screws, then
assemble it on the square stock to turn the round pulley mount and a
flange to keep it square. You could make the flange large enough for
screws to fasten the adapter to the pulley.

If the blanks aren't exactly at 45 degrees when you mill them both,
turn one piece around and it will fit.

I made a wrench for rusted brake line fittings this way except that
the groove is half a hexagon. The corners don't have to be perfect on
a wrench like this because it won't be used unless a flare nut wrench
has already mangled the fitting.