probing on all metal machine

[Washout]

Hi

I have the same situation - good conductivity throughout the machine (tool to bed).

For Z axis tool height I use a piece of copper faced PCB board which is wired to the probe input on my control board and a crocodile clip on the z-axis for the other end of the circuit.

For edge finding etc. I had to bite the bullet and buy a ruby tipped probe off of ebay, which was fairly pricey with import etc, but I needed it in a hurry to do some sub-frame mounts for a customer (after a couple of abortive attempts at trying to make my own - I nearly got there but couldn't get the bl**dy bearings to solder to the PCB permanently). Since I've had the probe its been great although I do have to go into config in MACH3 and change the probe to enable low if using this rather than the tool height which is the other way round.

Of course now I want an auto changer to switch the probe in and out and cutters, but I have other stuff to fit first ;)

[JAZZCNC]

I just use a piece of single sided copper PCB in a long thin strip. It's stable material and Mics up accurate enough for most work.

I use Shrink wrap the stuff used for wrapping pallets for isolating from bed it's wide and strong. Suppose Cling film could work.?