Should I Grind A 2nd Flat On My Motors?

[rb99]

My motors have only 1 flat spot, but my new pinions have 2 grub screws, presumably for shafts with 2 flats.

I am having the same old problem of the pinions coming lose, even though I am bending the key when tightening. I have yet to put Locktite on them, as I am testing the motor configuration. Historically I have reefed the screws so tight I actually have warped the pinion opening into a slight oval, as well ruining the grub screw head.

I could use a grinder to grind a 2nd flat spot, although heat may be a problem.

Any ideas?

[paul_z]

Can you put a second grub screw behind the first one?

Paul Z

[rb99]

I can still use both screws, I think it would be more effective with 2 flat spots.

[jerry_stanek]

are you tightening the screw that hits the flat first. You need to tighten it and turn the pinion until it is loose then tighten it down.

[rb99]

I think so but I will definitely try that. Thanks.

[Ajcoholic]

Most pulleys , gears etc that use two set screws at 90 degrees to one another only need one flat.

The second pinion puts pressure on the shaft to keep the first one from loosening up. Some don't even have a flat just two set screws at 90 degrees.

[rb99]

OK I will give it another shot with tightening the flat one first, really tight, then do the second. Both with blue Locktite this time.

[knight_toolworks]

I found the new pinions have smaller setscrews and you can't tighten them up as well.

[rb99]

I cranked them with Locktite blue. We shall see when the Locktite dries...