Demagnetizing tools

[David S]

If magnetic field strength is proportional to current x no of winds, you need to increase voltage with a transformer. Current and voltage are inversely proportional - if you increase voltage you decrease current.

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Well not quite in this case. He wants to decrease the power. Which means reducing the voltage, with something like a variable transformer, or a series resistor could be added, such as a 120 vac incandescent lamp.

David

 

[Mwmx54]

Thanks for the ideas, I need to do something as it is very difficult to use as is. It’s one of those things that now that I have it, I don’t know how I managed so long without one.

 

[rust rescue]

Lets not forget the old tried and true shock method. Just smacking the tool or part on a table edge will usually knock the magnetic flux around to do the job. Not suitable for every thing but effective for screwdrivers, wrenches etc. I am going to have to try the soldering iron trick.

 

[RJSakowski]

If magnetic field strength is proportional to current x no of winds, you need to increase voltage with a transformer. Current and voltage are inversely proportional - if you increase voltage you decrease current.

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Actually, for a constant resistance/impedance, Ohm's Law prevails; V = IR. Voltage will increase with current.

You are perhaps thinking of an electric motor where doubling the voltage halves the current but that is because to do so, you change the windings from parallel to series. This quadruples the impedance netting half the current while driving with twice the voltage.

 

[Be_Zero_Be]

There are several very good threads about homemade demagnetizers, here is mine :
Yet Another Demagnetizer

 

[agfrvf]

You can magnitize tools by beating on them or contact with a magnet.

 

[diamond]

Sorry about waking an old post but I just picked up one of these on ebay for $10 (free shipping and showed up in a couple days) It worked pretty darn well so wanted to share. My calipers had become magnetized (probably got too close to my mag bases one too many times) and was really annoying when little tiny metal dust bits got stuck to the jaws.

It took a couple times trying and I opened the caliper to max so I could do one of the jaws at a time. Doing both at the same time didn't work well. Once I did that, boom, no more magnetism and my calipers are cleanly hitting zero every time now.

I'd prefer making it but I didn't have anything lying around that would work so spending $10 was an easy fix.

 

[hman]

Looks like a very good tool! Does the magnetic field slowly go down, or do you have to withdraw the tool before releasing the button?

 

[Cooter Brown]

When Richard King came to my shop for the class he got frustrated with the scraping tools getting magnetized, so he bought a demagnitizer for the class just like this one..... I love it! I use it on just about everything in the shop.....


Thanks Rich.......

 

[gonzo]

I disassembled the transformer from a microwave. Then applied ac at about 25 volts to the secondary. Passing tools through the rectangular hole demags nicely.