TBD Supergrade Z axis

No real instructions came in the box. Just says take off the gear to the old NEMA 23 motor and install it on the new axis.

I did this and as you can see a slight gap between the NEMA motor and the top of the spindle rod.

Am I missing part of the necessary hardware or have I blindly missed a step in the install process?

Definitely confused as all hell.

Where’s the other side of that coupling? I believe you should have two metal sides and a rubbery insert that goes between them. Although I have no experience with the TBDCNC Z-Axis kit, I believe you should have a coupling similar to these.


I would contact TBDCNC if you cannot find the other half and the insert within your kit.


Brandon Parker

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I concur.

BTW - the stepper axle and screw (spindle rod) is not supposed to touch, but as Brandon says you are missing the other 2 parts of your 3 part coupler.

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That coupling needs to be quite tight tolerances too because they are like a lovejoy coupling and I know there is some play back and forth with them so I would make sure about that as well

Ended up just buying a new one from Amazon as they had next day free delivery.

Just happened to have 6.35mm coupler which is .01mm larger than a true 1/4" shaft.

I have to say super impressed with the build quality.

When comparing the OEM X-carve Z axis it makes me wonder why our machine does not come with a better z axis right out of the box.

It actually doesn’t make any sense to me why direct drive couldn’t be Incorporated rather than the small belt.

Seems like every little upgrade takes out a lot of slop and makes the cuts so much more sharp and accurate.