Help with calibration using Mach3

[rockaukum]

First off I do not have a MM machine but thought I'd ask here. I am trying to calibrate the motors on a 4x8' table with steppers on R P. I have it spot on for the Y axis. I got it close after four tries on the X axis. The Z axis is another story! I am using Mach3 to do the calibration. I have it set to inches and set the distance to one inch. Do the test and the Z does not move although I can hear the motor humming along then stops making the noise. I return Mach3 to run normally and manually adjust the Z without any issues at all. Any suggestions on what may be going on here? I started the calibration because I did a "test" cut and when the request for the Z to raise came, it would not come all the way up. If any additional information is needed, please ask and I will get it. I am very new to this stuff and don't fully understand so the help is very much appreciated!
Thanks,
Rockaukum

[danilom]

If you know how many steps it needs for your motor to make one full turn, and if there is any reduction in between you know the ratio, you also know the pitch of the Rack and the number of teeth on the pinion, so there is nothing to be calibrated in mach its just a number which you calculate... Racks if not precision are non linear so it might differ from point to point where you decide to calibrate.

it would not come all the way up

what does this mean, how do you know where should it come? do you have a tape measure? zero out the axis DRO ... measure from some point to the axis in question, move it (jog it, mdi move etc...) 100mm, measure again? did it move 100mm?

[rockaukum]

Thanks Danilom,
I did not build the machine nor have any specs on the machine or its components. I have tried to get this from the person I purchased the machine from. He has informed me that there were no such documentations. I don't really know what drivers are on this and not sure how to find out. I have been messing with this for a little while now and have found that I get one thing straightened out and another pops up. At this time, I think I got it. I figured out how to do the motor tuning which may have been the issue with the Z axis (motor humming and not moving, Stalling??) So I did a bit of motor tuning, then went to the calibration again. X & Y are good but the Z would move to the top and max out against the stop (no limit switches on the machine). Thinking about this, I came to a new trial. If it maxes out the movement with a one inch request, lower the request and see what happens. I went with 1/8" request and the machine moved a lot but stopped before hitting the stop. Now I was getting somewhere. Entered the measured movement and ran the calibration again, After four or five goes at this, I got it. Repeatable results! Life is good again. I am learning this stuff as I go and excited to see some results along the way. If you have any input as to figuring out the drivers (again, don't know where they are) that would be great. As well as finding out if they have any reduction...
Future of the machine... I want to install limit switches, Emergency stop buttons and a controller to adjust the router speed via mach3. Lastly build a vac table. One day, one step at a time... If ya got "how to" links to any of these additions please share.
Now on to figuring out inkscape and sheetcam....
rockaukum