# Demagnetizing tools and parts



## GailInNM (Jan 19, 2009)

My favorite, and only, grand daughter (7 years old) paid a visit to grandpa Gail's workshop today. I use a lot of small super magnets around the shop and she thinks they are great toys. After she spent about half an hour at my steel top workbench she had about 25 magnets scattered around the workbench. When she left I also had a variety of magnetized bits and pieces including 2 files, several hex keys, a couple of HSS tool bits, and a couple of parts for my current engine project. 

So, out comes my portable demagnetizer. It is an old Radio Shack hand held bulk tape eraser. Put the part against the face, press the button and pull the part away before releasing the button. Takes about 5 seconds. 

I won't admit to being an old Coot, but I bought this eraser when they were sold for erasing reel to reel tapes before cassette tapes took over. As soon I got it, it saw a lot more service in the shop. Few things are worse than a magnetic file that refuses to give up the filings. 

Keep your eyes open at flea markets, eBay, thrift shops, and garage sales. Going price for a used one on eBay is about 5 to 15 USD and about one or two dollars at the rest of the places. Well worth it as you can take it to your machine tool to demagnetize vice jaws and mounted tool bits. 

Gail in NM,USA


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## rake60 (Jan 19, 2009)

Now there is one of those "WHY DIDN'T I THINK OF THAT" ideas!

Great tip Gail!

Rick


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## joeby (Jan 19, 2009)

Good idea! 

 Now I have another tool to look for at the auctions and flea markets. I would rather make use out of old tools than look through the new stuff anyway, especially if it means I have to go into Wal-Mart!

 By the way, if you have a Weller soldering gun, you can demagnetize parts with it by passing the part through the loop while it's on. Any type soldering gun with a looped tip should work actually.

Kevin


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## Noitoen (Jan 19, 2009)

You can dismantle a washing machine's water pump motor, (in Europe these motors have a laminated metal core with one coil), cut the rotor hole in half, install it in a plastic enclosure (small Tupperware will do fine) with the coil inside and the core outside. Use a momentary switch to connect the coil so that it's only connected when you are demagnetizing.


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## Lew Hartswick (Jan 19, 2009)

I know no one here will be able to find one of these but: The thing I have used for 
nigh on to 3/4 century for de-magnitizing is the coil from an electro magnetic 
loudspeaker circa. 1930s. It was used as the filter choke in the power supply so the 
dc through it produced the magnet field for the speaker. I put a cord and plug on
it and it has enough inductance to handle 115 AC without any problem. Been using
it since I was in high school. They just dont make em like they use to. 
  ...lew...


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## mklotz (Jan 19, 2009)

Gee, I thought everyone had a bulk tape eraser in the shop. Absolutely essential tool.

If you have friends who are HAMs (amateur radio operators), ask them if they have periodic swapmeets. They show up there sometimes.

BTW, I don't know if it's necessary, but I always remove my electronic wristwatch before using mine.


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## Kermit (Jan 19, 2009)

You can MAKE YOUR OWN demagnetizer. It is the easiest of the electric gadgets to make and very forgiving of whatever parts you use.

You do not have to have segmented plates for a core ANY piece of soft steel or iron will work because you will not have in "on" for more than a few seconds. No chrome Moly or HSS Tool steel. Just simple annealed 1018 would be perfect. Anything close to it would be useable as well, but it must be soft iron or steel.

Radio shack sells magnet wire. You will need enough to make a coil with anything from 30 to 100 ohms of resistance. 100 being the target you should aim for.  A 28 or 26 gauge wire would be about right.  1000 feet of those would give you 80 Ohms and 50 Ohms respectively.  Wrap the wire around the steel in several layers. Try to keep it about the same thickness across its width. Finish it with some black electrical tape and attach an AC plug cord.

The device will draw about 1 or 2 amps and will hum and heat up if left plugged in too long... The user just places the object on the demagnetizer and then slowly removes it from the vicinity of the magnetic field. The slowly decreasing field strength that is changing polarity 60 times a second will flip fewer and fewer iron atoms as it is removed resulting in a fairly disordered arrangement of atoms. AKA DE-magnetized.


Anybody could build one of these,
Kermit


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## nobeard (Jul 25, 2012)

quick way is to visit local scrap yard remove starter solenoid from a pre engaged starter motor then remover the motor contacts and you have your coil wound for a 12volt supply and it already has a core connect it up and demag everything.


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## Noitoen (Jul 27, 2012)

nobeard said:


> quick way is to visit local scrap yard remove starter solenoid from a pre engaged starter motor then remover the motor contacts and you have your coil wound for a 12volt supply and it already has a core connect it up and demag everything.



Just remember! To demagnetize you need a coil with AC current.


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## abby (Jul 27, 2012)

What about a degausser from an old monitor ? I find the most annoying thing is when your measuring tools are magnetic , you are constantly wiping the blades of the calipers or the anvils of your mike.
I suffer a lot from it but the only magnet in my shop , apart from my tools of course , is the magnetic stand for clock gauges.
Do you think this is the cause ?


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## Rockytime (Jul 27, 2012)

abby said:


> What about a degausser from an old monitor ? I find the most annoying thing is when your measuring tools are magnetic , you are constantly wiping the blades of the calipers or the anvils of your mike.
> I suffer a lot from it but the only magnet in my shop , apart from my tools of course , is the magnetic stand for clock gauges.
> Do you think this is the cause ?



Hi Abby,
What is a magnetic stand for clock gauges. I am interested because I have been repairing clocks for over 30 years. Are you talking about a bushing system?
Les


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## nobeard (Jul 27, 2012)

yes you do need an ac supply but it isnt a problem as transformers only work from ac just remove the rectifier from a decent amperage battery charger


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## Forestgnome (Aug 20, 2013)

I use the Weller gun myself. Just gotta watch your fingers though.


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## Hopefuldave (Aug 24, 2013)

Les, I.think.by.'clock gauge' Abby means Dial Indicator', nothing specific to clocks!

Abby, any jarring or impact can cause iron and steel to magnetize, outside magnetic field supplied by the Earth!


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