Finding top edge

[compact8]

For touching off Z, I keep a 1/4" dowel pin next to the machine. Put the end of the cutter (not spinning, of course) about 0.2" above the work, lay the pin on the work and gently push it under the cutter. Now slowly raise the cutter. The pin will slide under as you get close to 0.250" and slip right through when you are exactly there. On a CNC or with a DRO you can set the display to 0.250" at this point. On a manual machine crank in 0.250 on the knee to get to the surface of the part.

Don't try to bring the cutter down onto the dowel, you'll damage the flutes. Always go up.

After doing it a couple of times you'll find this to be very fast and very accurate.

I have heard about using metal sheets of known thickness in the same way but using dowels should be better as metal sheets may not be flat after some use so the accuracy will be affected. Furthermore, the roundness of dowels should produce a sudden movement once it's cleared like the kicking of edge finders upon contact.

 

[Parlo]

An unusual method is to use a 90 degree head and an edgefinder.