I had a similar issue with a Shapeoko router. There was no continuity from the spindle rotor to the rest of the assembly. My solution was to mount a brush above the spindle motor shaft, to make contact on the end of the shaft, then bring that back to the sense input. And, yes, I brought a ground wire out to the workpiece to be sure the circuit would be complete.
--J. Ray Mitchell Jr. jrmitche...@gmail.com (818)324-7573 "No problem can be solved from the same level of consciousness that created it"Albert Einstein On Sat, Feb 16, 2019 at 9:47 AM Gene Heskett <ghesk...@shentel.net> wrote: > 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> > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
