Greetings all;

I've just found that because everything it painted before assembly, 
apparently including the inside of the spindle motor mount, that a 
ground to the bed frame can be anywhere up to 2 or more thousand ohms to 
almost anything else on the 6040, and apparently even includes the 
spindle bearings as part of the first 50 or so ohms.

The net result is that using the workpiece as one contact, the the tool 
in the spindle as the other for the alignment function is fraught with 
enough variables I could break a tool against the edge of the workpiece, 
even damaging the workpiece, before a contact is detected. Since there 
isn't Z room enough for one of those $65 spindle mounted contact 
detectors, and it would take at least ten feet of ground braid strung 
thru the cable chains to arrive at a decent ground on the motor housing, 
which wouldn't solve the problem entirely because of the oil film in the 
spindle bearings, how the heck do I arrive at a reliable connection that 
only responds to a contact between the tool and the workpiece?

A flying ground lead one could bring up and clip onto the tool would 
probably work, but sure resembles something Robe Goldburg would dream up 
as it would need to be long enough to reach the tool regardless of where 
it is on the table.

That, or using a much higher voltage limited to a few microamps so as not 
to constitute a shock hazard. But basically use it to measure the air 
gap. I could make that work even before a physical contact was made but 
thats not a tasty idea in the long view either.

Any other ideas out there? Hopefully something that doesn't involve 
changing tools to use.

Thanks all.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>



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