Chatter when jogging at around 30-35% speed

I’m having a problem with my new Foreman Elite series router. Whenever I try to manually jog the machine at 30-35% speed it will make a screeching type noise, then begin to chatter along the rails. If I do this at slower or faster speeds, it runs perfectly. I initially noticed the chatter when I was making a cut and it would do it during certain operations, like 2-3” radius arcs. I think the machine slowed to the corresponding speed where the chatter occurs during these operations on these cuts.

I’ve searched through the forums and tried every fix I can think of that could be somewhat related. Here’s what I’ve tried so far:

• Cleaned and lubricated ball screws and rails
• Adjusted and tightened ball screw nuts (White ones at end of rail)
• Insured rails are aligned properly (no twist)
• Insured machine is square
• Insured machine is level
• Took Spindle off to see if the extra mass was causing the shudder. (still does it with spindle removed)
• Removed motors and slid both axis back and forth to make sure there was no binding (both move freely)

To me, it’s almost like a harmonic that causes the chatter. I posted this video so you could see what I’m talking about. At 0:30 I change the speed to 33% and you can hear the chatter.


Please let me know any suggestions you may have to fix this.

Interested also my Elite Journeyman does the same thing at same speeds but so far only on the x rail movements. Tried some of the same things with no change.

Sent the same info to Onefinity. Thy are sending new motors and I’ll update once I install them.

Are the new motors the same or different than the ones being replaced?

Just received the new motors from Onefinity. They look the same as the original ones that came on my machine. Replaced my originals and jogged the machine around at all speeds trying to duplicate the problem I had before. Cannot make it chatter or or make any noises…runs smooth as silk! I’d say problem is resolved!

Can’t say enough for the customer support from Onefinity on this one. They replied to my email Monday night within an hour of me sending it (6:35 pm MST). Had a few emails back and forth that night and determined the motors were the problem. New motors sent out Tuesday morning USPS and I was emailed the tracking numbers. Received the new motors today with return shipping label for the old ones. Couldn’t be happier with how this was handled!


I also contacted support, explained the problem and included at video showing the differences when it was running at different speeds. There was an immediate response from them indicating that they were sending me a new motor.
It arrived in about a week and since installing it the machine is running very quietly and smoothly.

Thank You Onefinity Support.