[braddo]

Hey folks, I just picked up a Grizzly flex shaft and motor for light engraving in a CNC router. The handpiece seems pretty simple, with a little chuck on the bottom, two bearings fitting into a little tube. I notice that I can easily move the chuck side to side .5mm and up and down a little more than that.

This would be fine for hand engraving I assume, but I'm wondering can I put some shims in there to tighten up the movement? I don't think it's necessary to be completely concentric to the tube, but instead important for the bearings to be registered to one another and parallel.

I was thinking I could just try with a couple of pieces of aluminum foil on the same side on each, but not sure if that will shred on the way into the tube or later gum up the works while working. Perhaps there's a better material or approach.

Any other thoughts on how to improve runout on this decidedly budget spindle?

Thanks!

[braddo]

OK, on doing some research here it seems perhaps the best fix is not a shim (which I did find some) but instead some loctite/permatex bearing seat. Now, how to choose which one - there are lots of choices. Since I'm just trying to fill space between the outer race and the tube, and there will be no force on the race, that adhesion strength isn't a factor, just compression strength. Honestly can't imagine any type of epoxy not being strong enough.

Next question is how to get the bearings to be aligned... I wonder if the best thing to do might be to push the spindle against the side of the tube, assuming that the gap is concentric - even though the spindle won't be centered in the tube, the bearings will be as aligned as I can get them.

It might be possible to rig up some sort of runout test rig and push the spindle to one side or the other as the loctite is curing. But, seems like I'm more likely to just mess that up.

Any opinions?

Thanks -

[keebler303]

Pick one based on the gap you have: Loctite - Henkel

You can always shim the outside of the handpiece to get the spindle perfectly vertical. With tiny engraving cutters, it won't be too critical.