Magnetized lathe chuck

Dave in MS · Feb 12, 2011

I bought a 6 jaw chuck on line and the seller neglected to mention that it is magnetized. It is a real PITA because it collects chips all over the jaws as well as inside on the the scroll. Cleaning it out is not a fun job, and takes time away from the project. Are there any electrical experts on here that can offer an opinion on how to demagnetize this chuck?

Cub149 · Feb 12, 2011

Maybe a degausing coil from an old CRT tv or monitor.

bison · Feb 12, 2011

I would send it back

msb · Feb 12, 2011

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4ADFA_enUS370US371&q=demagnatizing+iron

Eric in IL · Feb 12, 2011

The tool/die shop I used to work in had a demagnetizer. No idea
what was inside the approx. foot square box. It had a foot
switch, you stepped on the switch, passed the part over the box
then raised the part away from the box while the power was still
on. You would have to disassemble the chuck and do it one
piece at a time.

Try calling your local shops to see if they have one you could
use for a couple minutes.

36 Coupe · Feb 12, 2011

Tv techs used a big degaussing coil that could be passed over the chuck.

Fred Martin · Feb 12, 2011

I used to know of a little local tool shop that used a large electric motor housing with the end bells and armature removed. They had it hooked up to electricity cause when they used it, it hummed. They would turn it on and pass whatever they wanted demagnetized through it and that took the magnetism out. Maybe some of the Sparkies can fill in what I don't know about it. Of course you can throw it down on the ground real hard and that will take it out too...it must disturb the arrangement of the molecules but, it is a bit rough on a six jaw! If you wrap a coated wire around a screwdriver a few times and then touch both ends on a positive and negative battery post, that will magnetize the screwdriver...if you reversed the wire and run it through the opposite polarity...would it remove it??? Let us know how you come out on it. ohfred

Russ from MN · Feb 12, 2011

I think a induction bearing heater would de-
magnetize it, the newer ones shut down slowly and
that is supposed to prevent bearings from becoming
magnetized. I have a little gadget from HF that
you can put a screwdriver in one hole and it's
magnetized and there is another hole that will de-
magnetize, don't know how it does that without ac
current, but it does!

XRogerX · Feb 12, 2011

For what it"s worth, a guy at work is doing his millwright apprenticeship. One of the questions on an exam was what would you do to demagnetize a gearbox that had become magnetized. The correct answer was to wrap welding cable around it and energize the wires. I assume that meant running an arc with a heavy current. I have seen welding cables in a loop suck together when the welder was running a heavy bead. I have never tried this, but I can understand the theory behind it.

johndeere720GA · Feb 12, 2011

I have demagnetized screwdrivers by striking the shaft on a hard surface. You may be able to smack it with a 3 lb hammer (remove it from the lathe first though) and get it to demagnetize you may have to hit it a couple of times (not hard enough to dent the chuck but a good sharp rap or so).

Dave in MS · Feb 13, 2011

I like the welding cable idea. Do I wrap both cables around the chuck or just one? If one, which?

Bob - MI · Feb 13, 2011

See if there's a company in your area that does magnetic particle inspection. They will likely have a de-mag coil and can do the trick for you in less than a minute. Look under NDT (non-destructive testing)

If you were here in West Michigan we would do it for free for you at our company.

BDT in Minnesota · Feb 13, 2011

I bought a vidio/audio tape eraser at Radio Shack about twenty years ago... Your question and my curiosity drove me to see if it would work on a flat 2"X 3" refrigerator magnet.... That magnet is now history; totally de-magnetized....

May take a few passes to de-magnetize the chuck;; but it should be able to do it..

Fred Martin · Feb 14, 2011

Nice reply Roger, reminded me of another fellow and I talking at the rear of a truck mounted SA-200 Lincoln portable while the owner started welding. Had a coil of about 50 feet of cable laying in back of truck. Everytime he started welding, the 7/16th inch wrench laying in the middle of the coil would stand straight up...when the arc was broken it would lay back down. So thanks for the info on the cables. Once in a while I find a piece of steel that I need at the Mall (junkyard) down the road. They use a magnet to unload a lot of it. I'll try your method. My mind don't work like it used to. Too much beer under the bridge, I reckon. ohfred

Dave in MS · Feb 14, 2011

One of my first jobs as a machinist was working for a grumpy old far- kind of like I am now, in a shop that rebuilt big electric motors. He gave me the chewin out of my life because I was welding about 5 feet from the machine, and had the cables coilde up and draped over the welder. He warned me to get those cables off the machine unless I wanted to buy it after I burned it up. When I asked why hanging the cables on the welder wasn't OK, he explained the magnetic field business.. I think I'll try wrapping the welder cables around the chuck. Might just work.

Russ from MN · Feb 14, 2011

If you use welding cables, I think dc would
magnetize, ac would de-magnetize, and I would take
the cables off while energized. the induction
heaters that de-magnetize shut down slowly.

Magnetized lathe chuck

Dave in MS

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Cub149

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bison

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msb

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Eric in IL

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36 Coupe

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Fred Martin

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Russ from MN

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XRogerX

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Dave in MS

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