Shapeoko 3 Owners with early model Z carriage CAUTION

Don’t damage or loose your eccentric nuts. They are not included in the Shapeoko Maintenance Kit for the 3. The kit has larger eccentric nuts that will not fit/function on your carriage. Carbide emailed me today saying they “no longer have any”, a nice way of saying we can’t support this part any longer. Without them you won’t be able to get the proper pre-load on the v-wheels.

And speaking of the maintenance kit for the 3, they include 3 pullies to replace on the Z and X/Y steppers. Unless you have a miniature gear puller for small stepper motors forget replacing them. They are a press fit on mine. "Hey Carbide, what is your plan for the customer to #1 remove, and #2 install soft aluminum pullies that are press fitted? I’ll need to be satisfied with just the new belts and v-wheels.

Scott, can you be more specific on your model? Perhaps the complete model number and date of manufacture? That would help pin down the problem. Thanks.

The specifics of this are:

  • the machine originally shipped with the same eccentric nuts as were used on the Shapeoko 1/2
  • said eccentric nuts were used on the belt drive Z-axis, which was designed to be as thin as possible so as to reduce lever effects
  • the machine switched over to the Z-Plus as a default Z-axis
  • the eccentric nuts were replaced with larger ones (which no longer fit in a belt-drive Z-axis)

For removing the pulleys, the intention there was that they allowed a Maintenance Kit to upgrade a machine from 6mm to 9mm belts — if a machine already has 9mm belts, then the pulleys are redundant spares, only to be used if a pulley is somehow damaged — usually they can be levered off with a pry bar and suitable fulcrum.

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Hey @metalbender, I have 4 of the original eccentric nuts that came with my Shapeoko 3 (the bottom ones in the pic; the top ones are the newer kind in the maintenance kit). If this is what you need, send me a PM and I’ll mail them to you.


I successfully competed belts and pullies on Z and X, tackle Y today. If I need an eccentric nut I may shout out. In the long run I may order some from Inventables, they are used on the Y plates.

For those that experienced a Z upgrade on their 3, did you notice a difference in performance?


The Z-Plus is markedly more rigid than the original belt-drive Z-axis, and can be pushed harder, esp. in terms of depth per pass.

The HDZ is that and more, and adds the advantage of being narrower, so increases the X-axis travel width, which was a boon when I had a project which otherwise wouldn’t fit on my XL (serial #0006 upgraded from Standard).

I will note that in softer materials, and for 3D finishing passes the belt drive is quicker/more nimble (and when it was first launched, it was stunningly so compared to the M8 threaded rod in the SO1/2 (for those folks who didn’t get Brandon Fischer’s nifty Leadscrew upgrade)).