Good way to remove coating from EMT

Does anyone have any good ways to remove all the coating from EMT. The coating is cause jittery movements on my x axis as well as loud grinding noise that is rather irritating. The grinding is coming from the middle assembly during slow movements. At first I though a bearing was shot cause i could feel the vibrations in one bearing more then other so I replaced it and it made no difference.

The Y axis moves nice and smooth at any speed not sure why just x is a problem. The steppers rotate nice and smooth so no problem there. Could it be an alignment issue in the center assembly? All my laser etchings come out with nice round O’s and seems to run very square.

Time to save up and go to SS tube I think. That crap is expensive in Canada :frowning:

Just thought of something… The bolts that hold the bearings in the center assembly I have them pretty tight would loosening them off a little help?

Make sure your bearings aren’t riding on the weld. EMT is welded into a tube, so there will be a small ridge, just turn it so it’s on the back side of the carriages.

I will check that… my luck it is riding on that ridge. Thanks Barry

Hopefully that’s what it is! Grinding off the zinc is a pain. Though I’ve seen people make an adapter out of a piece of allthread and a few rubber washers, kinda like the barrel sander bit for a dremel, then just spin the whole tube and use some coarse steel wool to smooth it out.

Quick muratic acid dip and a baking soda bath after and they could all be naked in a few minutes… Been looking into tig welding conduit and that is all that comes up. For the cnc, Maybe just a quick sand paper massage and call it good and probably safer.

We just used a flap wheel to remove the zinc about an inch or so around the weld area. Made a lawnmower trailer ramp hinge out of galvanised fence post that way. Still use a box fan to blow the fumes away from you though!