DIY Demagnetising tool that works

If you are like me, you can get sick of tools like screwdrivers, scribers and allen keys that pick up swarf because the tool has gradually acquired a magnetic field. I purchased one of those little demagnetising tools that have a kind of staircase opening inside a plastic housing but was disappointed with the almost non existent effect on the tool. I wanted to build something better but I also didn't want to use anything like a modified transformer since they looked a bit scary. What I came up with was a device that can be used in the drill press, lathe or even a cordless drill. It uses four rare earth magnets with alternating pole orientation which can be spun so that the magnetic field is rapidly switched in the presence of the tool. All you have to do then is to slowly withdraw the tool from the effect of the spinning magnets. That's it!https://youtu.be/bKNigMT0qq4

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Thanks Mark Presling! We've added your Demagnetizer to our Miscellaneous category,
as well as to your builder page: Mark Presling's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-demagnetizer-8"> <img src="/uploads/223403/homemade-demagnetizer-8.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-demagnetizer-8">Demagnetizer</a> <span> by <a href="http://www.homemadetools.net/builder/Mark+Presling">Mark Presling</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/demagnetizer'>demagnetizer</a> </div> </div> </div> </div>
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Very neat, quite ingenious.
I made a demagnetiser and magnetiser from a transformer. Sometimes a magnetised screw driver or allen key is very useful so I can magnetise and then demagnetise at will.

Well done, Mark! Thanks for the great video. That'll be on the must make list...I'm in the same mind as many, good to have driver bits magnetized SOMETIMES...and twist drills never....cheers
Jim in Sunny South Coast NSW

Quote:

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Originally Posted by Beserkleyboy

........ good to have driver bits magnetized SOMETIMES...and twist drills never....cheers
Jim in Sunny South Coast NSW

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That gets my vote.
Where on the south coast, I used to live in Cronulla, then Woronora.

Tony,
Shoalhaven Heads, east of Berry. Small world, eh? Emigrated from SF (Orinda/Berkeley) Calif in 87, lived and worked in Sydney til 2003, moved to Bowral, down to coast 2012...this is probably the last stop...but ya never know...cheers
Jim Pearson

Quote:

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Originally Posted by Beserkleyboy

Tony,
Shoalhaven Heads, east of Berry. Small world, eh? Emigrated from SF (Orinda/Berkeley) Calif in 87, lived and worked in Sydney til 2003, moved to Bowral, down to coast 2012...this is probably the last stop...but ya never know...cheers
Jim Pearson

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Jim,
I left for the UK in 1971 to race in the Isle of Man, ran out of dosh, so no flight home, and had to make a life in Europe. Been in Spain for the past 30 years.

Tony,
Travelled through Egypt, Spain, Morocco and Portugal in 2017. I could live in Spain or Portugal easily...but I'd have to brush up my schoolboy Spanish...Cheers
Jim

Congratulations Mark Presling - your Demagnetizer is the Homemade Tool of the Week!

Clever solution, and a great first-post win. You know it's a good homemade tool when, three days later, your build inspires someone else to build a similar tool.

Some more nice builds from this week:

$20 Tool Post Grinder by Welcome to the Machine
Ball Turning Device by Fintho
Simple Trailer Unloader by olefella
Drill to Mill Conversion by The Aussie Shed
Buffing Disc by Kovanca Polock
Magnetizer and Demagnetizer by tonyfoale
Table Clamp by Kwandotechnic
Half Step Ladder Attachment by rgsparber
Sand Muller by Bongodrummer
Bender by Bricoleando
Center Point Finder by Lahis
Axle Welding Fixture by Frank S
Rotatable Two-Tire Lift by racerdude31
Leveling Rake by frugalolegeezer
Bandsaw Fixed Jaw Alignment by rgsparber
Router Table by RCTURKA
Shark Tooth Scoop Shovel by frugalolegeezer
Shop Press Foot Cap Adapters by Unisawyer

Mark Presling - we've added your tool entry to our All Homemade Tool of the Week winners post. And, you'll now notice the wrench-on-pedestal award in the awards showcase in your postbit, visible beneath your username:

https://www.homemadetools.net/forum/...OfTheWeek4.pnghttps://www.homemadetools.net/forum/...eWeekIcon4.png

You'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and award choice and I'll get it sent over right away.

Nice work! :thumbsup:

hardly ever need to demagnetize anything usually I have the opposite problem I will need an Allen wrench or tool bit or screw driver magnetized for these I keep a small selection of button neo magnets in a wooden box When done I remove the magnet any residual magnetism left in the tool is fine by me if swarf becomes a problem just rap the tool against something to knock the swarf loose .
But I know that a lot of guys need their tools free of any residual magnetism your demagnetizer looks like it would fit the bill for that, good job

Mark,
Worthy winner.
I copied it and have now retired my transformer based device. Actually I want the transformer for another tool.

Tony,
I am glad it worked for you. Mine gets a regular workout. For some reason my shed seems to have a magnetic charge. I have heard that a nearby lightning strike can magnetise large structures. We get lots of thunderstorms where we live and we had a very close strike a few years ago that killed the quartz clock mechanism in our kitchen!
Regards,
Mark Presling

Congrats, Mark! Just btw, where are you that you get the lightning? Cheers
Jim on a beautiful early winter's day (23°C) in South Coast AUS

Quote:

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Originally Posted by Mark Presling

Tony,
I am glad it worked for you. Mine gets a regular workout. For some reason my shed seems to have a magnetic charge. I have heard that a nearby lightning strike can magnetise large structures. We get lots of thunderstorms where we live and we had a very close strike a few years ago that killed the quartz clock mechanism in our kitchen!
Regards,
Mark Presling

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Lightening can be destructive. A couple of years ago it destroyed the controller in a pellet fire heater as well as some UPS and other things. I made a new controller for the fire from an Arduino which works better than the original.
I use a some magnetic bars as tool holders and that is one reason that I sometimes need to demagnetise. When I saw your idea I knew that it would work but I was uncertain as to whether it would work well enough. It has proven itself on calipers, drill bits (I don't know how or why they get magnetised) and most screw drivers but I have one screw driver that refuses to be demagnetised. I wonder whether it is intended to be magnetised and perhaps has a magnet hidden in the handle. It is not strongly magnetised but it just will not give up what it has.

For bigger tools, I demagnetize with a bulk tape eraser (remember those?). For smaller tools I use my old Weller soldering gun.

However, when I saw Mark Presling's ingenious mechanical demagnetizer...

https://www.homemadetools.net/forum/...ol-works-72881

I had to have a miniature version for my in-house small job bench. Beyond its undeniable coolness, it would save me the trip to the garage to retrIeve the soldering gun and could be spun with any of the Dremel/Foredom-like tools lying on the bench.

I was fortunate to have some 1" fender washers with a 1/8" hole that just fits a 5-40 screw to provide a shaft to grasp in the Dremel. Six Harbor Freight 5/16" diameter super magnets were epoxied to the washer in an alternating polarity configuration.

Spun at even a low speed, it does a fine job of demagnetizing small tools.

Attachment 42713

It is now 3 years since I made my version inspired by Mark's. I made a stand alone version with the rotor driven by an old washing machine pump motor. The motor and switch are encased in a plastic junction box and sit on a bench permanently. It gets used regularly. I am still at a loss to understand how calipers get magnetised but they do, although not often.

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Thanks mklotz! We've added your Mechanical Demagnetizer to our Miscellaneous category,
as well as to your builder page: mklotz's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-mechanical-demagnetizer"> <img src="/uploads/255020/homemade-mechanical-demagnetizer.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-mechanical-demagnetizer">Mechanical Demagnetizer</a> <span> by <a href="https://www.homemadetools.net/builder/mklotz">mklotz</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/demagnetizer'>demagnetizer</a> </div> </div> </div> </div>
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Nice idea! This is my 2024 3D-printed version. Since it is plastic I don't have to worry for the magnetism of the stem.Attachment 47508Attachment 47509

Only after posting my thread did I notice that there was another one, containing a 3D file of this tool. Great minds think alike... :embarrassed: https://www.homemadetools.net/forum/...924#post133690
I happily adopted his concept.Attachment 47522Attachment 47523

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Thanks yair feldmann! We've added your Demagnetizing Tool to our Miscellaneous category,
as well as to your builder page: yair feldmann's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-demagnetizing-tool-2"> <img src="/uploads/269433/homemade-demagnetizing-tool-2.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-demagnetizing-tool-2">Demagnetizing Tool</a> <span> by <a href="https://www.homemadetools.net/builder/yair+feldmann">yair feldmann</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/demagnetizer'>demagnetizer</a> </div> </div> </div> </div>
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THANKS EXCELLENT. WILL BE VERY USEFUL

Quote:

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Originally Posted by Mark Presling

If you are like me, you can get sick of tools like screwdrivers, scribers and allen keys that pick up swarf because the tool has gradually acquired a magnetic field. I purchased one of those little demagnetising tools that have a kind of staircase opening inside a plastic housing but was disappointed with the almost non existent effect on the tool. I wanted to build something better but I also didn't want to use anything like a modified transformer since they looked a bit scary. What I came up with was a device that can be used in the drill press, lathe or even a cordless drill. It uses four rare earth magnets with alternating pole orientation which can be spun so that the magnetic field is rapidly switched in the presence of the tool. All you have to do then is to slowly withdraw the tool from the effect of the spinning magnets. That's it!https://youtu.be/bKNigMT0qq4

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