I challenge those who think they've solved the grounding issue to

take a 1" surfacing bit and try to remove .125" (single DOC) of thickness from a compressed PVC product such as:


I can literally hold my hand on the body of the router while it is surfacing while holding a metal chair and it will still cut out due to static. Not sure if there is a good solution here?

I haven’t had any issues when machining similar PVC, but got tons of cutouts (requiring SO3 reboot) when cutting Corian. I had to run the last ~2 min of the job multiple times to get it to complete.

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I have no issues unless running a surfacing bit. Can’t do more then 60-90seconds of surfacing. Its insane.

How are the brushes on your router?

Maybe you need a week off :joy:. I have to try to remedy this on my machine starting this week. It’s very frustrating when glitching at the frequency you mention. Can you use a smaller bit to get by until you can try to fix it?

Brand new router, maybe 10 hours total run time.

I don’t do a lot of PVC surfacing… so its okay for me, but i bet its a great repeatable test to see if someone can come up with a be all end all solution to this issue.

That could be it as well. I wonder if it’ll “break in”.

I’ve never surfaced PVC, so I can’t say it wouldn’t happen here.

I feel like you have probably checked this also… but I’m pretty sure it won’t matter if you’re grounding the router while it’s operating. The router is ostensibly already grounded via the 3rd conductor on it’s electrical outlet. I forgot that the hand router doesn’t have the ground conductor.

Every time I have had an issue (and come to think of it… seems that it only happened when surfacing mdf with a 1" bit), it was because my vacuum hose was isolated from the router and/or its bracket.

During normal ops, the hose would sometimes flex during a rapid change in direction, causing the hose to tap against the router or bracket. If it had enough static at the time, that’s when it would happen due to the sudden transient. So I could either ensure that the vacuum hose stayed in contact, and allow the potential to escape through the router to its ground, or I could ensure that the hose never touched anything during operation. Of course, the second option means that it will be building a lot of static, and it still could find a way to discharge in an unpleasant way.

Anyway, that was my rigged solution, and it seemed to do the trick. Most folks recommend a more elegant solution like an anti-static hose and/or conductive wire wrapped around the hose, terminating at a solid grounding location. Another thing worth mentioning is that some people seem to have found at least a little success with plugging their cnc into an uninterruptible power supply, but I feel like that is more for the disconnects related to power transients from an unstable electrical supply.

I’m new, so this may be common knowledge. But I had disconnect issues with mine recently. I did some testing and narrowed it to only those times my dust collector was running. So I wrapped a bare copper wire around the DC hose and grounded the end nearest the collector to the building ground (which is also connected to the router ground, computer, S3 power supply, etc.). I’ve not had a single disconnect since. I’m following this topic because I plan to machine PVC soon. HTH.

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Have you

  1. Tested the continuity to ground of your Z assembly and X beam?

  2. Used a conductive anti-static hose for dust collection (if present) and grounded the hose?

If you’re using a ‘trim router’ these are generally double insulated, don’t have an earth wire and neither the outer shell nor the collet has any path to ground. When you’re generating all that friction with the big surfacing bit you’re basically got a big van de graaff generator running and you’ll need some properly thought through paths to ground for all that charge that isn’t the stepper motors and Carbide controller board.

The human body is not a great conductor. To discharge the amount of static electricity you’re generating, you should have a copper wire run from the router body directly to the nearest ground. Use a power (house) ground, not any ground on the controller board. The bigger wire you use, the better. I assume you will want stranded wire so it can flex easily.


Out of curiosity, where do you live? Humidity can play a big factor in winter, and I’ve heard second hand of someone fixing their static issues by bringing a pot of boiling water into the shop…


Mark and I live in a similar area, I know in my basement shop the relative humidity has been hovering around 30% during the winter.

@wmoy yeah its winter… 20-30% and I’m sure thats a factor, but to clarify my issues are… no other issues in any other material other than surfacing bit on PVC. I used to get issues in surfacing my MDF waste-board but those are long and gone.

I’m familiar with most of the fixes discussed and I’ve implemented some but not all. But I’m betting this is the extreme test to see if you’ve succeeded.

I don’t know which router he’s got, but my Carbide router is double insulated and it’s only got a 2 prong plug so there’s nothing grounded on the router

a few guesses
Drape some anti-static tinsel and run it to ground. (cheapest, easiest)
Place some ESD tape under the material and again, run to ground. (almost as cheap but not re-usable)
an Anti-static Ionizer (a bit pricey)

As to the router, new does not mean it came with a good set of brushes. I would check that first as it is available and no cost, inspect the brushes for even wear and good contact and clean the housings before re-installing.
If you can be careful, hold your hand close to the material while surfacing it, you can feel the static build up in your arm, (hairs will start to stand) and expect the strong static discharge when you do contact grounded objects…dont use a finger tip, enough charge can split the fingernail, discharge it through the palm of your hand…
Trying to diagnose a problem through chat is like calling a Doctor and saying, I Don’t feel good, fix me…the Dr. may say take a few tylenol and get some sleep, but that does nothing for the Dodge truck sitting on your foot…


Yes its the C3D only two prongs.

You’re absolutely correct. My mistake, I completely forgot that they only have the 2 prongs.

Would it be at all feasible to run a ground wire from a know-good ground to the PVC project? Run the ground to a clip and clip it to the pvc piece?
Just thinking outside the box…