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New to Surface Grinders

GDS12

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Has anyone on here had experience rebuilding an electromagnetic chuck? I want to replace the cable that connects the chuck to the power supply/controller. It is starting to crack and was already spliced once before. I removed all the screws from the base plate but it doesn't appear to want to readily separate. Any pointers would be welcome...
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Cadillac

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I’ve rebuilt acouple permanent mag chucks but not a electrical one. Might be better to just use a good electrical tape and go over the whole cord. Most likely it has the splice from someone removing. Maybe put a plug instead of the splice to avoid cutting when needs removed.
The bottom of the chuck usually has screws that sandwiches the top middle and bottom. Don’t try and remove the top it will be hard. The seams might be siliconed for waterproofing. Use a thin paint scraper to separate. Mark all your pieces so you can put back the same way. If disassembled you will definately have to regrind the chuck once remounted.
 

GDS12

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Well as I carefully worked to separate the sandwich the top came off. Actually it looks like it doesn't really matter if either the top or base came off because it appears to be made symmetrically with either acting as opposite poles. The inside appears to be completely potted with some sort of firm compound that fills all the open spaces. I think the white junk may be congealed coolant that seeped in over the years but in any case it doesn't look very promising for a rewire job...

I am hoping that someone can correct me if I am wrong here.

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Bob Korves

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The electromagnetic chuck I took apart was not potted like the one you are showing. On mine, which I got from H-M Member benmychree along with my B & S 2L surface grinder, the cord was easily accessible inside the chuck, and it was pretty easy to replace the cord. H-M member Donald Youngling did the work after I gave him the chuck, which is a bit too small for my 6 x 18" grinder, but usable on his T & C grinder. I already had the chuck ground on all sides, my practice piece for learning how to grind a mag chuck. Shiny on all sides and with a new cord, the chuck looks very nice. We also made a electromagnetic controller for the chuck, using a drum switch and a variac, among other components, to control the voltage and also demag the chuck by reversing the current flow while dialing down the voltage, all manually. It works!
 

GDS12

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I have the controller and variac so that part is good. I like the idea of just putting a connector on it and then I can wire up the other end to the controller. It will look neater that way and enable me to more easily move the chuck without the other components hanging onto it.
 

Bob Korves

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The components should be remote from the chuck, stationary, and away from grit and coolant.
 

GDS12

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The controller and variac were both mounted on the side of the base under the table and quite honestly were covered in grit. I think you are right that it makes sense to mount them a little more remotely. Have you seen them mounted separate from the machine like on a wall? I wonder what most people do with their controllers when they are equipped with e-magnet chucks? Variacs with grinding dust in them can't work too well.
 

Bob Korves

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Get it up higher than the table, and farther away at the same time. Gravity pulls the grit down. Still, have it in easy reach. The right side of the grinder is much cleaner than the left side, if you have the common clockwise running spindle. On a wall is a good choice, if is close to the grinder. The controller needs to be in easy reach.
 
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