Gantry is jerky...

[threadfx]

I've been having a time with my ShopBot. The gantry movement isn't very fluid and is causing irregular cuts. It isn't real apparent in wood, but when I am cutting plastics it's very apparent. Cut speed makes some difference, but it's still there cutting at .5 IPS.

I haven't determined if it is a single axis or a combination of the X & Y. Everything seems to be adjusted right. The rails are clean and everything is lubed.

Is there anything I can check or adjust to get rid of the excessive movement?

[Dick McGuire]

Aaron,

For sometime I had excessive amount of chatter marks even when using a new 3-1/4 hp PC router. The bearings in it finally failed and when I mounted another new PC router the amount of chatter mark were reduced alot. Conclusion: bad bearings in the first router.

Could this be your problem?

[gerald_d]

Aaron, suggest that you start out by testing the SB on another PC that is slightly higher spec. than the one you are using at present.

[Richard Sears]

I had the same problem and I tried running in DOS instead of windows and for me that cured it.

[studebaker]

I had a problem similar to your gantry problem. The allen head set-screw on the pinion gear was slightly loose.... The mis-positioning was pronounced in just one axis and one glitch for every revolution of the stepper motor.