[Clockwork]

I came up with this idea a few weeks ago.

Spray a tiny shot of spray glue on a small strip of aluminum foil.

Press foil on one corner of the wooden blank leaving some of the foil dangling over the edge.

I use a cheap multimeter with a continuity buzzer to perform the calibration. Just about any continuity tester will work. You can also make your own with a LED + resistor + battery or Buzzer + battery.

Attach one alligator clip to the dangling foil and the other to the bit.

Lower the z axis slowly until continuity occurs.

The Z axis is at now at zero.

This should be good enough for woodworking - you can always mic the foil and add the difference for greater precision.

Comments?

[jimini]

A couple of years ago Balsaman had a superb idea, based on the same procedure, I believe he used it as sort of a limit switch to find zero.

[jimini]

A couple of years ago Balsaman had a superb idea, based on the same procedure, I believe he used it as sort of a limit switch to find zero.
With this idea, you'll need to have your Z home to top of work piece.

Check this:
http://www.cnczone.com/forums/showth...saman+set+zero

[tahustvedt]

I made a connector on the gantry for the limit switch circuit and use an aluminium plate and a crocodile clamp to create a circuit as the tool is jogged down slowly. As the tool touches the aluminium plate the limit is toggled and it stops and I get an accurate height with all my tools. Once the tool touches the plate I type in the thickness of the plate in the Z-coordinates ont he screen.

Before I made the limit switch cable I used an ohmmeter to check for contact as I lowered but that was tedious and more manual compared to just lowering until it stops by itself.

[Glidergider]

If you are using Mach3, there's even a better way then those mentioned above. I'll find the link and post it here if you want it. Maybe you've already seen it?

[Glidergider]

Here it is for all you Mach3 users. It's the best way to zero your tool.
http://www.cnczone.com/forums/showthread.php?t=36099