[theRat]

Hi,

Can someone tell me if there is any issue with permanently connecting the group wire for the probe permanently to the spindle body (rather than using an alligator clip to connect it to the endmill when needed)? I can't think of any problem since the spindle body should be electrically isolated from everything else.

Thanks
Simon

[PlanetCNC]

You can and you should. Spindle body should be grounded.
But spindle body and endmill are not electrically connected on all spindles. Specially if tool moves electrical connection through rotating bearings is very week. But if you determine that this is not an issue on your machine then you can do it.

[CitizenOfDreams]

I mounted a brush contact touching the shaft on the top of the spindle. My spindle is a small 400W BLDC motor:

[PlanetCNC]

This is from one of our test machines.

[theRat]

Thanks guys, I think my spindle has a good connection already, but will check it out with a multimeter while turning the spindle by hand to confirm.