I've been looking for an edge finder solution for a 1/8th inch collet machine such as one based on a Dremel tool spindle or similar smaller tooling. Does anyone have such a solution? I'm currently using a Wolfgang Engineering TB-650 spindle that only comes in a 1/8th inch collet size.

In the mean time, I have also started work on making one that combines it with a probe interface on my CNC control board. Much like an auto-height setter for the Z axis, it would be used in the X & Y axis to find the edge and automatically set the DRO to 0.0 once the edge has been located. If there is any interest, I'll try to make some available at a reasonable cost. If not, I'll just keep it to myself The parts are on order and I'm expecting to be able to locate edges within a tolerance of 0.001" reliably, but I won't know until I get it fully put together and tested.

The basic design is to have a 1/8th inch hardened stainless steel rod (about 2 inches long) with a slightly larger stainless steel tube around it on the lower half of the rod. Both parts will be separated with a thin rubber insulator. To use it, you would simply attach both sides of your probe interface (ground + probe, one each to the rod and tube) with alligator clips to the edge finder. Inside your control software, you would hit the button corresponding to the axis you want to locate. The machine would then slowly push toward that edge until the probe is tripped, stop and set the DRO to 0+thickness offset. The idea being that once the tube has contacted the material and flexed toward the rod, it will make electrical contact and signal the probe interface to stop. The expected air gap between the rod and the tube would be 0.0175", so not a lot of movement would be required to trigger the probe. Thoughts?