I purchased an arduino and a 3 axis stepper motor(tb6560) after finding 3 stepper motors from cd roms. I hook them up the way the grbl wiki page says, and downloaded the universal gcode sender. I ran the gcode sender, and can move the stepper motors using the directional buttons. It works best with the step size set to .02. Whenever i upload gcode though the stepper motors will only move one click before stopping, even if it goes way past that. Any ideas? Is it the example gcode i used, or the controller/ stepper motors.
If you hook up a terminal program to communicate with your Arduino (instead of the gcode sender) you can display or modify the GRBL settings.
I forget which terminal program I have used to do that, but there are a number of them that are available - I believe that you can even use the Arduino IDE as a terminal program. Your gcode sender must be shut down so that it is not hogging the serial port used by the Arduino (over USB).
Do a search for GRBL commands for more info - with the latest GRBL version (at least), if you enter $$ into the terminal, it will list the current configuration, including the $8 value that I mentioned above. You can change the value by entering something like $8 = xxx (where xxx is the new setting).
I'm not really sure - there may be an interaction with the other configured settings.
So I might try setting it to half of its current value to see if that makes any difference in the behavior of the motors.
BTW, I'm not sure how the 'step size' setting of the gcode sender translates into actual machine commands - so instead you could try inputting some simple Gcode manually and see how it responds - maybe make a relative move of one step, then several steps, etc.