Shark CNC: Loose spacer on Z-axis screw?

Continuing the discussion from Shark CNC: Want to get certified to use it?:

Thanks again to @csader for training me up on the Shark. I came back and did my first little practice project today. It performed nicely, but along the way I noticed this odd semi-loose piece that is floating on top of the threaded section of the Z-axis screw (it’s pretty obvious, but I added a handy arrow to the photo below… :cowboy_hat_face: ). It just sort of hangs there and wobbles as the screw drives the spindle up and down. It doesn’t appear to impede normal function.

I peeked into the mechanism a little bit and I don’t see an obvious place where it should be or what exact function it serves, but obviously these things don’t appear out of nowhere…

Tagging other likely interested parties: @JoeN @TravisGood

Thanks for pointing this out James. I’ll be in within the next couple of days and can take a look. Given this is a custom Z axis that I wasn’t involved in building, hoping @JoeN or @EricP might know if that is a critical piece?

The plastic ring thing was part of the original assembly. I think it is a dust cover. I believe we don’t need it it. The ball screw is mounted into the stepper motor via a flexible union.

Oh, good. In that case, we can just be mesmerized by how it wobbles gently on the z screw as the spindle jogs up and down. :cowboy_hat_face:

Unexpected entertainment


That is actually a dust cover for the ball bearings in the ball screw, it goes down by those 3 screws. It would be good to reinstall but probably pretty tricky. will need to raise it up the z till that base is just below the non-threaded portion of the shaft then pop it back in.

I’ll be in tomorrow morning and see what I can do

Oops. I forgot that there was an upper ball bearing

Not as entertaining as trying to parse the grammar in Shark CNC dialog boxes… :cowboy_hat_face:

Semi-seriously, we might want a little checklist reminder that includes “No, Really, Just Click Yes” on the contact plate dialog. That approach makes my CNC safety instincts twitch, but perhaps it is arguably better than leaving it as an “exercise for the reader” to guess which button applies to reality.