Centroid Community CNC Support Forum

I am in the process of converting my PM-728VT to CNC.
Looking at the installation manual under section 7.3 Fine Adjustment, using gauge blocks for turns ratio adjustment.

I understand the process in principle, but it says to create a fixture that is 'L' shaped. What is the 'L' for? I would think any standard about 12" long would work -- as long as it's dimensions are precisely known?

Thanks

Kevin

Anything is ok to measure the distance of an as long as possible gage block in one direction...

Uwe

The "L" is so you can start on the edge of long end of the L and then zero the DRO. Then jog straight up with Z and then move towards the short end of the L the known distance. The short end of the L is for the stop at the known distance. Just as the pictures show you in the manual on page 107. You need a stopping point to measure up against with your dial indicator.

Whatever you use for calibration travel the longest, precise distance you can to calibrate. The longer the better. Don't just move one inch and call it done. I use a set of precision gauge blocks and can gang the 4 longest ones together and move 10".

If you want an accurate machine be sure and repeat the process over and over until you get a repeatable number. Again, this is not one and done. The procedure is explained very well in the install manual.

ShawnM wrote: ↑Thu Aug 21, 2025 9:40 am The "L" is so you can start on the edge of long end of the L and then zero the DRO. Then jog straight up with Z and then move towards the short end of the L the known distance. The short end of the L is for the stop at the known distance. Just as the pictures show you in the manual on page 107. You need a stopping point to measure up against with your dial indicator.

Ok. Got it. The end block is so both measurements are in the same direction, and you don't have to adjust for the DTI ball diameter.

Thanks !