Demagnetizing tools

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Tozguy

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I have this demagnetizer
https://www.jensentools.com/general-3601-magnetizer-demagnetizer/p/424-597
that I am trying to use to demagnetize some Allen keys. I follow the instructions but can't get rid of the magnetization.
It would be interesting to learn how they get magnetized unintentionally so it could be avoided but till then I would like to be able to demagnetize when needed.
Is this the right tool? Can I expect to remove the magnetization completely using this tool?
Thanks.
 
kev74 said:
I bought this beast last month and it works well. It sounds like something out of a Frankenstein movie when its on, but works well enough that a screwdriver or other tool won't pick up chips after I run it over the demagnitizer.

https://www.ebay.com/itm/L-W-Demagnetizer-L-W-Chuck-Co-Bench-Top-Demagnetizer-110-Volt-60-Cycle-A-C/232999642527?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I haven't seen to many positive comments about the small demagnitizers.
Click to expand...

I also have a L W demagnetizer of the same era. Rather than the bright yellow finish mine has a crackle enamel finish. I believe it was built in the late 1940's or early 1950's. I've had it about 20 years. It gets used a couple times a year to demagnetize screwdrivers, pliers, wrenches, etc., etc. On occasion I've even had to demagnetize a lantern post tool holder. How it ever got magnetized I'll never know, but it only takes a couple passes through the field to demagnetize it. It's interesting that it's made by the L W chuck company. I have several L W chucks for one of my lathes, however none has ever needed to be demagnetized.

The key to Demagnetizing a tool is to run it through the magnetic field several times. By "running through" I mean to pass it over the machine about 3" above the plate. If you want to magnetize something touch it to the top of the machine for a couple seconds.

If yours is still missing the light bulb I would replace it. If I remember correctly the cycle time is only a couple minutes or so. If it's left on too long the transformer will overheat and melt the insulation.

As for the one the OP linked, I noticed it said it was for "small Parts". I would venture to guess the Allen wrenches have too much mass for the magnetic field of the small permanent magnet to penetrate.
 
Tozguy, if you figure out how to get it to work please let me know 'cause I've tried them on and off since I've had my own tools without much luck.
 
kev74 said:
I bought this beast last month and it works well. It sounds like something out of a Frankenstein movie when its on, but works well enough that a screwdriver or other tool won't pick up chips after I run it over the demagnitizer.

https://www.ebay.com/itm/L-W-Demagnetizer-L-W-Chuck-Co-Bench-Top-Demagnetizer-110-Volt-60-Cycle-A-C/232999642527?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I haven't seen to many positive comments about the small demagnitizers.
Click to expand...
I have one of those L-W demag boxes. Got it from Benmychree. It works great, loud hum like most of the better ones have. Will take larger work than small ones will.
 
kev74:

https://www.ebay.com/itm/L-W-Demagnetizer-L-W-Chuck-Co-Bench-Top-Demagnetizer-110-Volt-60-Cycle-A-C/232999642527?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Wowsers! Shipping's gonna get ya on this one!

PS -there's a previous thread about tool demagnetizers here:
https://www.hobby-machinist.com/threads/what-do-you-use-to-demagnitize-your-tools.51704/#post-433183

It includes details of a mag/demag I cobbled up from a motor stator. Later on I found some PTC resistors, which I added to the circuit. These resistors initially have a low resistance, which rises as the resistor warms up with use. Great for demagnetizing - the AC magnetic field starts out full strength, then tapers off. No need to slowly withdraw the object. Details of the PTC addition are in post #109 at:
https://www.hobby-machinist.com/thr...ntrol-circuit-wanted.57733/page-4#post-489158
 
Tozguy said:
It would be interesting to learn how they get magnetized unintentionally so it could be avoided but till then I would like to be able to demagnetize when needed.
Click to expand...

I have no idea how tools become magnetized, but they do. As far as I know there is no way to avoid it. Even ships can become magnetized and need to be degaussed. http://navymuseum.co.nz/degaussing-ships/

The power demagnetizers work the best. I think mine was made in the '30s or '40s just by the look of it. Never tried one of the static demagnetizers.
 
I use the Neutrofier demagnetizing feature on my surface grinder to de mag. tools. At work years ago, we used a big DC motor field coil plugged into 110V A.C. for the purpose.
 
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