Hi @mynamejefff,
You may or may not believe me, but here goes.
There are no intrinsic design flaws in the SO3 that would have been “fixed” in more recent models, I’ve been using a standard size SO3 successfully for 4 years (some folks much longer than that), and hundreds if not thousands of other people too. BUT it’s a CNC kit and everyone’s use is different so statistically speaking there are a variety of hurdles that can present themselves. I’ll try and give you a few tips that helped people seeing similar things in the past on the forum.
The Z inconsistencies can be due to:
- zeroing somewhere that is not consistent with where you defined the zero point in the design file. Often times when people see the machine cutting air, it is because they set the zero reference to “stock bottom” in CC but actually zeroed on the top of the stock. It’s an easy mistake, I’ve been there.
- slippage of the endmill inside the collet due to inadequate tightening force, or dust in the collet, or a plain defective collet.
- use too aggressive plunge rate and losing Z steps, which messes up with the Z0 reference.
- using the BitSetter but not quite following the recommended process, in particular swapping the tool without using the “Load New Tool” button or when prompted, results in a wrong Z offset then being calculated when starting the job
- on belt-driven Z axis, loose setscrews on the Z motor pulley
- a problem in the Z wiring to the controller. The Z motor may be getting spurious pulses. Quite the unicorn, but theoretically possible.
The EMI gremlins are often related to sub-optimal grounding of the machine and dust collection, but since you went through fixes with support already I won’t mention the usual suspects again, however you may be interested in this thread: Grounding your Shapeoko
The X and Y offsets, in my experience, relate to the following root causes in 99% of the cases:
- lost steps due to too aggressive feedrate or the router/gantry hitting a hard limit or the endmill hitting a clamp
- loose set screws on a motor pulley. If you haven’t already, you should definitely inspect EACH pulley and make sure one set screw is aligned to the flat on the motor shaft, and both set screws are tight.
Your description of things working “for a while” and then getting X/Y offsets makes me think the pulley set screws hypothesis is likely (the setscrews could be tight enough than it works most of the time, but slips when there is extra force due to the toolpath or material being cut)
If you are willing to work with the community (along with support depending on where you are with them), we can probably figure out what happens and get your machine to a reliable working condition. Call me biased but my SO3 has been a workhorse, so there is no reason why yours shouldn’t be the same, but it’s likely that it will take some effort to go and inspect it mechanically, and possibly review the kind of setup/workflow you are using.