Do’s and Don’t of buying a used CNC

What are some of the buyer bewares of buying a used Shapeoko and what should you want to get?

We have a bit of a page on this at:

one big consideration for the SO3/4 is that buying a Maintenance Kit:

(be sure to select the right machine from the drop-down menu)

will pretty much allow rebuilding a machine to like new.

Other considerations are:

  • condition of MDF baseplate (SO3 or 4 w/o Hybrid table)
  • which Z-axis (for SO3s — our current machines all have Z-Plus or HDZ Z-axes, while the SO3 was introduced w/ a belt-drive, which while speedy, required a more delicate touch when cutting since it lacked the mechanical advantage of a screw drive)
  • which control board (for SO3s) and which connectors are present/absent — if you buy a machine which doesn’t have a BitRunner connector, but want that accessory or a VFD spindle you’ll need to replace the controller — going further back there were controllers which lack the PCB Expansion Adapter needed for the current proximity switches
  • whether or no the machine has homing switches (SO3) — if the machine doesn’t have homing switches you’ll need to use older or other software, or an MDI command to home the machine
  • which version of Grbl is installed — usually this can be reflashed, but it may be more expedient to buy a new controller

as well as the more obvious:

  • which spindle
  • what tooling is bundled
  • what accessories
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When buying a used machine it must be demonstrated by carving a project. If it is taken apart or not set up to actually use I would pass. Now if they discount it enough that is different. You can get parts for all the Shapeoko machines but if it is broke that is a cost to consider in your negotiations to buy. Since you dont know what you dont know I would stick with a working machine that can be demonstrated. The SO3 is a great machine but the original belt drives are not the best. If they have a Z-Plus then it is a very good machine. The SO4 and SO4 Pro are a better choice due to the fact they are newer and were an upgrade on many mechanical features over the SO3.

If I were to buy a used machine I would pick something that needs to be carved like a vcarve and/or advanced vcarve and that would prove the machine is working. Also all the accessories like bits and BitSetter and BitZero are additional cost items if the used one does not come with those accessories. So again that would need to be reflected in the price for a bare bones machine.

Recently someone here on the forum offered an SO4 ProXXL for $2000.00. I have seen SO3 from between $1000.00 and $1500.00 depending on the setup. Those prices are a general ball park and can vary. You can go on the c3d site and see what prices are for a new machine you might be looking at for an SO4/SO4 Pro/HDM/SO5. So a good rule of thumb would be 1/2 the price of a new one. The advantage of a new one is it is new and will not have been abused and you get a warranty. A used machine can be a bargain because after you use your new machine it is used but with a warranty.

I have bought and sold a lot of stuff on craigslist. Shapeoko machines do not show up very often but tends to be a slow mover. The audience for a CNC hobby machine is pretty small compared to someone buying a car or other commodity item. I generally price an item for 20% more than I actually want. People feel they are getting a bargain from the asking price. So if I want $80.00 I list it for $100.00. Anybody on craigslist that is experienced does the same thing. So there is always room to bargain. So I suggest you make a low ball offer because you can always go up. If you offer too much it is hard to go down from there. You never know if they will take what you offer and you get a better bargain. Usually people just want something gone they are selling.


If it looks well used/dirty and/or the seller seems to not know much about it, I would avoid it. These machines can be used regularly and if cleaned and maintained still look and perform virtually new. I would want a clean, well maintained machine, demonstrated.

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