Anyone have a idea how to build and use a touch plate setup on a taig mill I am using a Gecko 540 and Mach3 with the mill I searched the forum and got a little info for what the touch plate does but do not find details on how one would be hooked up...

Any posted designs and details anywhere?

http://www.cnczone.com/forums/showthread.php?t=36099

Its actually pretty simple to do, I tried something similar with a little 7/8" square of scrap brass stuck on the mill table with double sided foam tape to electrically isolate it from the table and to give it a little squish were I to overrun my tool. One wire goes to this plate, and that's about it.
The tool grounds out through to the mill itself (As long as you haven't gone over to ceramic bearings yet), so you can attach the ground anywhere.

I haven't gotten fancy with it yet, so far I was just lazy and to test it clipped the wires to my ohmmeter - pretty easy to when contact is made, and to see the circuit go open when you back it off and contact breaks.

I'd eventually like to code something trick into Mach to touch off and zero the tool automagically one of these decades, but realistically its kind of WAY down there on my priority list right around learning Swahili and forming a clog dancing all-tuba Sabbath cover band...

If someone else is interested in coding something like that to share, I'm sure it would be much appreciated by all!

Or here for xyz touch probe.
http://www.cnczone.com/forums/showthread.php?p=436270#post436270

^^ Awesome thread... just awesome. :D (the xyz touchprobe..) Didn't realize it was that easy.