CNC Touchoff

Touchoff pad for a CNC mill. It is highly likely (unless you took intentional steps to avoid it, or you are using a Shapeoko with a nonconductive bed, etc.) that your CNC structure is grounded. So this includes a plastic T slot nut and plastic pad to insulate from the machine.

This is a snug fit on a 7/16" T slot. Insert 8mm hot melts into the back end of the T nut ensuring it is recessed enough to not touch the bed. PRO TIP: Thread the bolt through the T nut out the back end and finger tighten a hot melt on a few turns. Insert soldering iron. The brass hot melts will heat up long before the steel fastener does, and the fastener will keep the hot melt aligned in axis with the bolt hole.

For the top touchoff pad use two countersunk bolts to secure to the table.

Finally, you need a 1" diameter metal puck. I used aluminum, about 15mm thick. Face and chamfer. Then chuck it up in a vise and face off a flat and drill/tap as M3. Thread your probe wire through the plastic touchoff h