Another digital calliper question

Hi folks, I have a set of Mitutoyo callipers I thought were stainless, but the jaws have become slightly magnetised. It's a real problem because even if you wipe them clean before zeroing (A P.I.T.A.) there are always fine bits of swarf that bridge the gap as you close the jaws & become trapped. (The jaws must be opposite poles) I can easily make up an AC fed coil to demagnetise them but the question is will that cause a problem with whatever suplies the counting circuit. All suggestions welcome, hope you are all having a great Easter. Ian Sutherland, Down Under.

Reply to
Ian Sutherland
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No problem, I hit them with a demagnetizer often. That swarf if annoying.

Reply to
Tom Gardner

Stainless can become magnetised. Some types with a magnet, some only after the part is stressed a bit. Degausser is an answer.

Reply to
Ian Stirling

Hi guy's, thanks for the replies, after reading the first one it took about 30 seconds to find a coil, hook it up to a ac supply & demagnatise the callipers. What a difference, put them in the chip tray & they came out with nothing adhering, what a difference for zeroing. Thanks again, Ian.

Reply to
Ian Sutherland

Can't remember the technical reasons( long time since college!), but Stainless that can be heat treated/hardened is generally of magnetic grade, try a magnet on your kitchen cutlery, the knives will be magnetic. Mark

Reply to
Markgengine

Not that simple. Some iron containing alloys are non-magnetic. Some alloys with no iron are magnetic.

Reply to
Ian Stirling

All Steels contain Iron by definition. The difference is in the crystaline structure-Austenite/Martensite, generally governed by the carbon content. Just to add more to the discussion, if you heat any iron containing alloy above the Curie point it will become non-magnetic, ( typically 300 to 400 deg C ) Mark

Reply to
Markgengine

Some grades of stainless steel have iron, some dont. Those with iron will be magnetic. :)

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irc

Reply to
Jim K

All steels contain Iron, even stainless steel. Not all stainless steels are magnetic.

Reply to
Ian Stirling

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