Spindle stuttered in middle of project and resumed 1/4" out of line

I was cutting a pine holddown and was midpoint and just happened to be watching and the spindle started what I would describe a stuttering for a few seconds, seemed to make many small motions (X and Y) and then resumed, but resumed approx 1/4" north of the line it had been cutting and then continued on this new path as if nothiing had happened, but 1/4" off.

My machine is 500x500, with the stock quiet spindle. I was using a 1/8" 2 flute bit at the recommended speed and DOC.

I can see no obvious problems with belts or wheels. Just finished running this same item earlier today.

Any suggestions as to what happened or how to correct? Hate to see this happen again and ruin a large project with expensive wood.


my belts looked tight when this happened to me, however they only need to slip a little to go out. a double check may be in order.( i put two tie wraps on each end of the belts and this worked for me. hope this helps. :slight_smile:

First check to make sure everything is still tight including your drive pulleys, make sure all electrical connections are still good (prob not the electrical connections if it continued like normal). If all is still good have you adjusted your pots yet? Does your machine make rouge movements when your spindle is on vs sitting idle (indication of a failing spindle)?

Those are some questions that kinda need to be verified before the true cause can be found. But it does sound like you missed a few steps and all of the above could be the cause.

Actually, that does sound like an electrical connection fault. I had the same issue when I added a molex connector to my wiring loom. There was an intermittent connection problem in the pins and it would cause the Y axis to not step, but the X and Z axes were fine. When I could hear the bad connection arcing and sparking and fizzing I decided to cut the molex out and solder the connections back.

Check your terminal blocks on the machine, and check the connections on the G shield. Make sure everything is tight. If you’ve added any other connection points along the way, check those as well. You may want to invest some time and money in crimp ring or fork connectors for the terminal blocks, and some ferrule ends for the G-shield just to ensure trouble free connections.

Hi Guys,

I have run several of my hold down without a repeat of the stutter, before doing the maintenance as suggested.

I rechecked all my connections and a few were not as tight as when installed, but none “wiggly” loose. I have tightened up all connections, reset tension on my “Z” wheels, checked "X’ and “Y” wheels which were OK, finally tightened my belts a bit. A general maintenace.

Thanks again for the suggestions, I’ll plan to recheck these items more often.