Ping Jim Wilkins

I got a call from a guy who has a repair job on a Blanchard grinder mag chuck in Portsmouth NH that requires someone with
electro-mechanical troubleshooting skills. I've worked on one as a favor a couple times for a mutual friend, but it's not really my department, and I don't have time to help him out. IIRC you're in NH -- any interest? Should pay well.
He assures me it's cleaner than the typical Blanchard grinder, but I wouldn't wear your good clothes. <g>
--
Ned Simmons

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It isn't my department either, I might have seen one once. http://www.brentwoodmachine.com /
jsw
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On Sat, 3 Mar 2012 16:08:42 -0500, "Jim Wilkins"

If you have any interest at all don't let unfamiliarity with Blanchard grinders deter you. General knowledge and troubleshooting skills are more important than familiarity with the specifics of the machine. I learned everything I know about electromagnetic chucks repairing my customer's similar machine.
There's a simple DC supply, the chuck controller, a commutator under the rotating chuck, and the electromagnet itself. It sounds like up 'til now they've just been replacing parts instead of doing any real diagnostics. The electromagnet has been rebuilt, and the controller replaced with a modern unit.
The machine in question is blowing fuses in the magnet supply. My recollection is that the chuck supply is 240VDC at a couple amps, so it doesn't take much swarf in the wrong place to blow the fuse. The first time my customer's grinder displayed the same symptoms it was a blown selenium rectifier in the DC supply; another time it was crud shorting the commutator.
--
Ned Simmons

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