Disconnect with Walnut

I was running a project today with my Shapeoko 4 Pro. Cutting through some 3/8 inch walnut. Got several disconnects at the same spot each time i ran the project. I’ve had my machine for approx 18 months and i have never had a single disconnect before. I haven’t checked the brushes on the router yet but do you think that the router brushes could be the issue.

Yes, usually when a disconnect arises after a period of successful operation it is caused by the carbon brushes in the trim router wearing.

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I just checked the brushes and i don’t see any excessive wear. A little bit of carbon on the sides of the brushes but that’s to be expected. I have a spare set of brushes so ill just change them out. I was using a depth of cut of 0.100 on an 1/8 inch bit on 3/8 inch walnut. I use 0.100 depth of cut a lot on hardwood but never had an issue, only when i am cutting all the way through the stock. I’ll Just try new brushes and see what happens.Thanks for the input

If switching out the brushes doesn’t work i have a Dewalt DWP 611 router that i can switch out. But i believe i have to order a different mounting adapter for this router. Can someone tell me which one to order for the Shapeoko 4 Pro. Also the body of the Dewalt router is longer than the Makita but there is an adjustment trim ring which i assume i would adjust so the drop below the mounting plate is the same as the Makita. Anyone have any experience with the Default router, same, better or worse than the Makita

Usually folks remove the adjustment ring.

To mount a DeWalt:

Thanks, i would think i need to replace my dust boot that came with the machine also?

Usually folks run dust shoes until they either get scuffed up and cloudy, or the bristles are damaged to the point where they won’t contain dust.

I meant if i change to the Dewalt router, it has a different diameter than the Makita so i would need a different dust boot.

Yes, the one that is used on the Carbide 3d router would not fit.

After the spindle bearings went out in the router that came with my Pro4XXL, I installed a Makita router, and haven’t had any problems. Instead of fishing the powercable through the cable chain again, and as the powercord is shorter on the Makita, I immediately voided the warranty on the Makita, and swapped the cords out.

Good point, you’d want the 69mm Sweepy v2:

Do the worn brushes cause a bunch of EMIs that cause the disconnects??

The Dewalt has a longer body than the Makita/C3d. So if you have a Z-Plus that would be a good thing. The Z-Plus has a history on the forum of not going low enough. Now on some Z-Plus they have a mechanical problem with the anti-backlash nut coming loose and restricting the movement down. Any as @WillAdams pointed out the Dewalt is 69MM where the Makita/C3d routers are 66 MM. On the SO3 the mount was 69MM with a 66MM Adapter. On the newer machines the 66MM mount was standard.

I have an SO3 with HDZ and have a Dewalt router. I have only had to change the brushes once in 5 years of running the Dewalt. The Makita/C3d seem to need their brushes changed more often. It may be the compound used on the Makita/C3D router brushes that just wear faster.

The main difference between the Dewalt and the Makita/C3D router is the Makita/C3d router can run slightly slower. The collet on the Makita/C3d routers are not attached to the collet nut so sometimes the bit sticks in the router shaft. The reason is when you loosen the collet nut on the Makita/C3D router it down not pull the collet down. The only thing that releases the bit on these routers is the expansion of the spring action of the collet. The Dewalt has a Porter Cable style collet that the collet is attached to the collet nut so when you loosen the Dewalt collet it physically pulls the bit/collet down.

I typically run about 18000 RPM so the Dewalt is in my opinion a superior router to the Makita/C3d router. So unless you specifically need to run 10000-30000 RPM for the Makita and the Dewalt runs from 16000-27000 RPM then the Dewalt is a great choice. However if you consider having the price of a Dewalt from $100.00-$150.00 and the Makita 701 $76.00-$100.00 and the C3d router $80.00 and the C3d ER11 Collet Router for $150.00 and a new mount for the 69MM at $80.00 it might more cost effective to just stay with the Makita/C3d router.

Mileage varies.

Thanks for the input everyone. For now i’m just going to change the brushes on the Makita and see if that helps.

I had the same problem when I first got my machine. I switched the router to it’s own outlet and the pretty much stopped the disconnects. Then it started acting up again recently, but only when I would do keyholes. I figured after almost 3 years it was brushes. I went to swap them out and to my surprise they were not very worn, but the inside of the cover was covered in sawdust. I blew that out and it was good to go. Now I make a habit before I run the machine to give a quick blast of air.


I place an old sock over the top of my router to try and filter some of the dust out before it get inside.


At the drug store buy ladies socks that are made like panty hose. The ones that just cover foot not regular sock length.

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Great idea. Will have to try that

Changing the brushes on the router didn’t help. Moving the router to a different circuit seems to have fixed the issue. Well see.

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As an EE, I can tell you that motors are notorious for injecting a lot of noise into your systems, both conductive, back through the cord, and radiated EM noise. Fluorescent lights are also nasty.

If brushes don’t help, ensure that all of your equipment that is plugged into the mains have a good ferrite choke installed on the AC power cord. The choke blocks AC noise both from going into and out of your electrical devices. They are only a few bucks and easy to snap on around your AC cords.


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I already have 1 ferrite core on the router cord near the router. But i could add another one on the other end. Maybe one on the shop vac too because its on the same circuit