Hi, I am a newbie to the forum and to CNC machining. I bought a Chinese 3020 and have a problem with a grinding noise coming from the stepper motor on the X axis positive when jogging, and then it appears to be across both axis when running a program, for example a circle where it becomes very noisy as it gets toward the zero movement. I have played with acceleration and had slight improvement, but the problem is still there. Also interchanged the motors to test, and the problem remains mainly on X axis. Sometimes the motor will actually stall. Any help would be appreciated.

Not familar with the 3020.
I would assume that you have recommended settings that came with the machine for Mach3.
Grinding sound can be indicative of a number of things. The first that comes to mind is the drive amp settiing and also a bad  signal that is generated by the computer through the parrallel port.  

Rich

Thanks for the response, Rich.  I will try another computer.

Hi,
    I had the very same problem when my 3040 was new. After weeks of trying to sort it out we found
a damaged wire to the motor making the noise which made it loose signals. The wire had a small cut in
the insulation which opened and closed as the machine moved and the wire rolled up  therefore
interupting the signal. 
I advise check and replace (if required) any suspect wiring.

Regards
Roy

Hi Roy, Thanks for the advice, I shall get some cable and try a rewire ...  I tried another computer as suggested by Rich, and that did not work. Regards.