Z Axis lead screw rises on some cuts

I’m attaching a photo, in case I’m using the wrong terms.

Essentially, when cutting a tough material like aluminum, the z axis fails to cut to the correct depth, and instead the lead screw and bearing sit higher and higher on the motor plate. This happens even when materials do not cause any issues when cutting them from the side. The bit is plenty sharp, but perhaps not ideal for plunging.

This is what I mean:

You can see the bearing for the lead screw resting a couple of mill higher than it should.

Some Y Axis upgrades have the motor sitting atop the lead screw, and wouldn’t have this behavior. I am thinking of making a change to one of them. Is there something I should try first?

I looks like you installed the bearing on the wrong side of the plate. The bearing should be installed on the bottom side of the plate and held in place with two screws. The bearing flange should sit inside of a pocket and will be flush to the metal plate surface and held in place by the two screws. I found that adding a little thread lock in the bearing pocket would apply additional holding strength for the bearing and prevent any movement of the bearing.

Check assembly instructions for the Z-axis flange bearing.

Z-axis Rail Picture.

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also notice that one side of the plate has a recess for the bearing to sit into. (also note the bearing has one side with a lip and the other is flush). Put the side with the lip into the recess and then the screws will hold it in place. I notice that in your picture that you have the lip on top and no recess as shown in the assembly instructions.

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Oh for crying out loud. I have been running like this for a year.

Thanks a lot for pointing out what should have been obvious Ken & Kenneth. Simple enough to fix, though I guess now I’ll be trading those inaccurate depths of cut for a few more broken bits.