How to "De-Magnetise tools

ddmunroe

ddmunroe

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I've never really been able to solve this problem ... EG : My verniers at the measuring points touched a neodium magnet once and since then it pick's up all sorts of steel when placed anywhere. Always having to clean off fine bits before use now.
Same thing with allen keys these seem to be already magnetic.

My plight is how can I "demagnetise them.

I've done the usual google reasearch a while back and found articles about heating things on or past the "currie' point etc but in the case of my verniers I can't do that. I tried heating up the allen key in question but it made no difference.
The one thing I haven't tried is an actual demagnetiser, looks like a crack detection transformer type tool.

Has anyone had success in this area ?
Thank's
dd
 
ddmunroe said:
I've never really been able to solve this problem ... EG : My verniers at the measuring points touched a neodium magnet once and since then it pick's up all sorts of steel when placed anywhere. Always having to clean off fine bits before use now.
Same thing with allen keys these seem to be already magnetic.

My plight is how can I "demagnetise them.

I've done the usual google reasearch a while back and found articles about heating things on or past the "currie' point etc but in the case of my verniers I can't do that. I tried heating up the allen key in question but it made no difference.
The one thing I haven't tried is an actual demagnetiser, looks like a crack detection transformer type tool.

Has anyone had success in this area ?
Thank's
dd
Click to expand...

An actual demagnetizer will work fine. I bought a nice, but really old (1930s maybe?), tool room demagnetizer a while back for $50 and I don't know I lived with out it. I hate magnetized tools.

I have heard that recording tape bulk demagnetizes will work, but I suspect they might be a little on the small side.

Also it might be possible to use an AC arc welder. An old buzz box would be the best for this to get a nice clean sign wave output. Wind the stinger cable around a piece of plastic pipe, connect the ground lead to the stinger, set about 80 amps, and turn on the welder. Pass to tool through the pipe a few times. It should be demagnetized.

I have used this trick to magnetize steel using DC from my Syncrowave, but have never tried to demagnetize.
 
Find an old CRT monitor and rob the degaussing coil out of it. Wire a momentary contact with of the proper rating and put the tool within the ring, hit the switch and slowly withdraw the tool. When it is a foot or more outside the coil, let go of the switch. Might take a pass or two, but will do it.
 
Tony Wells said:
Find an old CRT monitor and rob the degaussing coil out of it. Wire a momentary contact with of the proper rating and put the tool within the ring, hit the switch and slowly withdraw the tool. When it is a foot or more outside the coil, let go of the switch. Might take a pass or two, but will do it.
Click to expand...

Or just salvage the PTC thermistor with the coil and use that. The PTC has low resistance when power is applied and so initially alows lots of current to flow. As it heats up its resistance rises so that the current exponentially decays to near zero. As the current is AC the material in the coil is left with no residual magnetism. That's how the degaussing coil removes magnetism from the shadow mask.

I've got some degaussing coils. One of these days I'll get around to doing something with one of them.

You can also make a pretty powerful degausser from a junk induction motor.
 
I use a tape demagnetizer, the kind they used for reel-to-reel players, and they work really well.
 
For small things I've just taken a coil of wire, like hook-up wire and wired it in series with an incandescent bulb, maybe 60 watts or so. That works fine.
 
If you have a gun style soldering iron, the kind that the soldering element has two prongs that connect to the gun. Pass the magnetized part in between the prongs of the soldering gun while its turned on , instant demagnetizer. Works great with anything small enough to fit between the prongs. take care, JR49
 
I have an old jeweler's demagnetizer that was used to demagnetize watches. Tony's suggestion is a good one if you can't find one of these. They aren't too common.
 
The PTC John is referring to above is a special kind of thermistor with a rather sharp cutoff, like a switch. Sure, you could do that, and it would work. I just prefer manual control, and like that rather than of a relatively rapid collapse of the field. Moving the item to be de-magged out of the field slowly seems to work better. But that's just me. His suggestion is sound.
 
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