I have managed to slightly magnetise a rather expensive digital caliper, despite the metal parts being stainless steel, which is causing havoc with all measurements when tiny pieces of swarf are trapped in the jaws. Not having a proprietary de-magnetiser I wonder if there is any domestic equipment that I could use to do the job. I know the technique is to slowly draw the tool away from a rapidly changing magnetic field, but I can't think of anything suitable.
Cliff Coggin.
Two easy answers come to mind: either search on eBay for "degausser" or try dropping it in an East-West direction :)
Dave
Don't try heating above the Curie point!
If you have a bit of experience with electrics, and know what impedence is, it's not too difficult to lash up a degausser. Find a coil with a few hundred turns which will take "mains". You might use a field coil out of a dead motor, or the coils from a dismantled transformer. Pop a current limiter (like a mains light bulb) in series if you aren't sure if you have enough impedence. Put the caliper jaws in the centre of the coil, power up the coil and withdraw the caliper to a foot or so away over a few seconds before switching off the power.
Or try an older hi-fi buff, who may have a tape head degausser.
Get an old mains electric motor and whip the rotor and ends out of it. Connect this up and pass your part thru the hole in the middle.
.
Radio Shack used to sell de-gaussers for not very much, but perhaps they didn't work very much either!
Steve
This works fine but turn the power off before it turns into a magic smoke generator! 10 seconds or so is safe but longer periods risks overheating.
A similar trick is to dismantle any small mains transformer that uses "E" and "I" laminations. Throw away the "I"s and reinsert the "E"s into the winding.
Steel drawn slowly across and away from the exposed "E" ends will be demagnetised. Same overheat warning.
Jim
That might make your eyes water
Regards, Tony
The coil out of a cheap AC motor, with the rotor removed.
Remove the rotor, and if you feel flash, wire in a momentary contact switch, so that it only energizes when you want it to.
Power it up, and put the affected part in between the ends where the rotor was, and draw it away slowly.
Done.
Cheers Trevor Jones
If you still have a friendly local TV engineer he will have a degaussing coil, alternatively putting it on top of your TV when you turn it on might help.
...Won't help much with an LCD or plasma TV of course!
Regards, Tony
Gave my age away a wee bit!
If you have an AC coil type "Instant" soldering iron, pass the item slowly through the external loop. (With it switched on of course ;-))
Pass it through a couple of times and the last time take the item to be demagnetised a couple of meters away before you switch off.
Jim Ford
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