No Keyway, how to modify my pulley?

This is the Motor pulley I plan on using for my current build. I don’t have a keyway on my motor shaft but it does have some flat spots filed onto it. If I drill a hole in the pulley between the teeth for a set screw is this going to cause me any issues? Has anyone done this?

That should be perfectly fine. Use as big a grub screw as you can though for extra strength. M5 at least. Make sure you get perfectly in-between the teeth and have zero grub screw protruding above the surface where the tooth from the belt will rest.

Okay thanks for the advice! I’ll give it a go.

just use loctite 648; remove keyway and grubscrew :slight_smile:


M5 is a massive screw though. M3 with blue loctite should already be fine when there is a flat spot on the shaft.

  1. Another option is to drill and tap the shaft to same threading of your intended grub screw.

  2. Wrap the motor in plastic and shave a flat spot on the shaft for the grub screw to sit flat against it. But leave the tip of the shaft round, if the pulley does start to slide up the shaft it won’t come completely off.

I’ve done option 2 as the first one I may screw up the tapping in the shaft. Like what @longhairedboy did

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True, but I’ve found M3s to be not up to the job, even with loctite.

Hmm 648?,… do you know the difference from the loctite i use ,… High Strength 262 ?

loctite pulley retainer works a treat!

It’s a pulley retaining compound - not the normal thread loctite.

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Just use the green loctite (648) and put in on the shaft without any screws. it s working great ! if you have to remove it someday just a heat gun and it will come of.