Key way and Set Screw orientation

[SEK_22Hornet]

I am working on a belt drive conversion for my Grizzly G0704 mill. The motor drive gear was a press fit on the shaft with a 4mm keyway and key to hold in place, and a snap ring to keep it from coming off the shaft if it ever got loose. I am using stock drive parts to build a cog belt drive. The spindle pulley is done and seems to be securely mounted to the spindle. On the motor pulley I had first tried a single set screw with no keyway. It came loose very quickly. So now I will be cutting a keyway in addition to the set screw. My question is, where, in relation to the set screw, is the best location? Should I put directly 180 degrees from the set screw or is there a better location? The shaft is a 10mm diameter shaft (steel) and the pulley I am using is this one.



I intend to grind a cutter to the right size and make an adapter to hold it in the spindle. Then use the vertical travel of the quill of the mill (not turning) to shave out the keyway in the aluminum hub. I'll clamp the pulley flat to the table and use the table position to control the depth of cut. Any suggestions? Thanks -

Dan

 

[iron man]

We use to put one right over the keyway do a quarter turn and place another.

 

[stevecmo]

We use to put one right over the keyway do a quarter turn and place another.

+1 That's pretty much standard practice.

 

[12bolts]

Yep ^
2 screws at 90 deg. 1 bearing directly on the key.

Cheers Phil

 

[brucer]

I would probably use some red loc-tite on them also

 

[SEK_22Hornet]

I'm leery of locktite with anything that has plastic - I've seen it destroy a plastic part in anywhere from a few days to a few months, so I don't think I'll use locktite. As for having one under the set screw, that would certainly be a location that I would prefer, but I'm not sure that there is enough material to allow the keyway and still have meat enough for the setscrew, since this is a metal hub in plastic pulley. I do have another all aluminum pulley with a larger hub that I can use if I have to, but I wanted to stay with the plastic one, to start with anyway. I'll do some measuring and see what will work out. I may look into setscrews that have a patch of locking material on them, since I beleive the problems that I have seen in the past with plastic parts is more due to the solvents in the locktite. Thanks for the suggestions!
Dan

 

[Bill C.]

+1 That's pretty much standard practice.

That was I was thinking. I would make sure the face of set screw is flat. If he was using a set screw without a key way I would use a cone pointed set screw to penetrate the shaft. They can be a bear to remove the pulley from the shaft afterwards but it shouldn't slip.

 

[RandyM]

That was I was thinking. I would make sure the face of set screw is flat. If he was using a set screw without a key way I would use a cone pointed set screw to penetrate the shaft. They can be a bear to remove the pulley from the shaft afterwards but it shouldn't slip.

Not if you flat the shaft. Highly recommended, I do all mine that way.

 

[Bill C.]

Spot drill the shaft, then use the cone point set screw, not as likely to slip and it won'kick up a burr that makes the pulley hard to remove later. If the holes in the hub are deep enough use two short set screws in the same hole (the second locks the first).

Good advise, I've repaired pulleys that had a locking set screw on top of a regular one.

 

[24more]

I work in a large power plant and we use the. One over the key, quarter turn for the other. Double your set screws, instead of a long one use two shorts in the same hole. A little blue lock tite one the outer one. If you have a set screw that is flush with the outer material you could peen it with a chisel or punch.