Making a tool demagnetizer out of an old shaded pole motor to demagnetize HSS bits and drills and to magnetize screwdrivers or whatever else you can think of!
In another life I used to make those motors. We supplied Dayton with motors, but it is not one of "mine," as we painted all the rotors green. The copper hoops are shading rings and that's where the term shaded pole motor comes from. I ran the lamination machine for a bit, also painted rotors, made up the rotor and shaft assemblies and ran the gearbox department for awhile. All of these motors will run at 1200 rpm, so a gearbox was quite common to slow down the drive shaft. Thanks for the memories!
Thanks for sharing your story. I always enjoy hearing about how things are made and the people who make them. The processes and techniques. It's all interesting to me. 😀
Just made one for myself, and it worked great on some watchmaker screwdrivers and tweezers. Used a microwave fan motor, and wrapped all the bits of exposed wiring in electrical tape, just to be safe. Thanks for a great video!
That motor is also found in most microwaves. It's the fan motor. I made a similar one. Try putting a piece of foam in the opening with a hole in it. It helps guide the piece without touching the sides. Makes it a little easier for demagnetizing.
Made one of these up today using an old microwave fan motor. Slotted out the top of the armature aperture and I was able to successfully demagnetize my 6 inch digital callipers which had become very annoyingly magnetized. Worked a treat ! Thanks a lot for posting this very effective and useful information.
Great Video - thanx for sharing. For those of us that despise getting shocked and make it a habit of staying away from electricity :) - you can make a similar tool with 2 old hard drive magnets and a 3/4" PVC coupler. I taped the magnets on opposite sides of the coupler, held my wife's jewelry tools inside the PVC for a minute or so and they are completely de-magnetized. I did the same for a couple of screw drivers I've had hanging from those same magnets for the last year - de-magnetized them too. Thanx for the idea!.
Hey thanks man I've been searching for this method for an hour now. My drill bits are getting magnetized due to some electromagnetic projects I'm working on but it's been years since I've needed a powerful demagnetizer. Also, those secondary windings on that Ac induction fan SHOULD be insulated with an enamel but I put that in caps because it's possible something abrasive wore it down. If you have any tool that can check continuity just test a few places to see if any bare copper is exposed. Only while it is unplugged and removed from whatever circuit you found it in. I get heaps of these from bad microwaves and in some rare cases could share a connection to the 2kv capacitor. Some of the older caps did not have a built in resistor to drain it and people died touch them. Anyways, it's completely safe so long as it's disconnected from any potential power source to test cont and still safe to rewire for this purpose. Thanks again for sharing this I've been trying to remember this for over an hour now.
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@@damienkinchen we cant see it just as a dynamic that creates an economic loss because i have to admit that ive always very much enjoyed fixing everything that breaks. Since i was a boy it was the most enticing prospect to me. While all the other kids played with the toys they got for christmas i was to busy taking mine all apart to see how everything was engineered lol
Thanks for the idea. Looks simple and would be fine for the type of problems that I have with my tools. Some of the ideas below look like they are worth trying to make the demagnetizer stronger if I need it. But, your idea is probably easiest to start with.
I will try out to de-magnetize my preamp audio tubes it will work since I can put it inside the hole ! Oh yeah thanks for sharing I just have an old microwave oven I will use for this !! Great find !
Good video. This type of motor is also found in bathroom fans and old record players. I also, just saw a a guy tearing apart an air pufifier, with the same type of fan motor.
You want to take the coil out and put your tool in the coil!! You put a big ceramic resistor in line with 200 to 400 ohms 10 or 20W to keep it from burning up, and a push button switch, then to magnetize you fire it up with the tool inserted, and leave it in when you turn it off. To demagnetize you pull the tool out before you let go of the button.
microwave ovens,bathroom exhaust fans,toaster ovens with a circulation fan, lots of other consumer products use these shaded pole motors. you could even use a stator winding from a car starter motor or alternator but that would be a little harder for most people to get there hands on
i made this magnitizer and it works perfectally. i have suggesstion for this project. if u connect it in series then u can avoid overheating of coils and i did so and it works in that way. thanks for great project.
A shaded pole motor has a rotating magnetic field, and it isn't in the direction of the length of the tool, either, so actually it does a crappy job. It would be better to use the nice fat square-holed solenoid from the motor by itself and, if you need to, put a 20-40 ohm ceramic 10W or 20W resistor in series with it to your pushbutton. It will have the most amazing ability to magnetize or demagnetize a tool in under two seconds and it won't overheat with the resistor limiting the current. I've built a lot of these for friends. Just always use a momentary pushbutton, because if you leave it on a minute it will catch fire. ALl commercially sold demagnetizers have a warning to that effect, it's unavoidable without a much bigger device.
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Thank you so much for this video. Just first off you use a mounted camera and I didn't vomit from motion sickness watching. But really every couple of months I load up a box of drills, end mills, n other tools and take to a shop where I worked as a teenager to demagnetize. Now I can do it here at the farm shop. Now a question. How to make it work as a bench top meaning like the ones you lay a bigger tool and rub across it? Tomorrow I'll ride over to the local appliances repair shop and get a couple of these old motors and build one for sure. But at times demagnetizing parallel bars and such would mean the flat top type. That's again.
Hey great vid. If you want to de-mag a screwdriver or something, you simply place a magnet at the tip and drag it to the handle and lift away. To re-mag, you would place the magnet at the handle and slide down, right off the tip. I never tried it on a tool bit but it might work to place magnet at the tip of the tool and move to the other end and lift off. Curious to know if it works... Cheers
3-phase electromotors have a few construction (standart, 2-speed, combined construction, alterable-frequency etc...), but it is another story. By the way - heat is the less of problems (just to notice a work time- no overheat). I can get 1 to 1,7kW 1-phase electromotor for this action, but huge of problem is that to does it run on large items?
Thanks for the info! I pulled a sp-61k25 motor out of a blower vent for a bathroom and it works great to demagnetize things. It doesn't however magnetize anything really. Is there a significant difference between the motor I used and the one you did?
OH WoW! So if I take, for example, 4kW electromotor stator and do as You, then in same this WAY can I de-magnetize greatest items - lathe chuck jaws, caliper, vise case, wrench or item who includes much pieces??? Does number of phases is lot sense - 1 or 3 phase (230V or 400V)? I have pile of expensive items what are useless because they are magnetic.
I machine a lot of 300 series stainless steel. Sometimes it well become slightly magnetic when machined (what slightly means I don't know). Customers reject these parts saying its not 300 series, even though I have all necessary paper work and lab reports confirming its is 300 series. any advise would be helpfull. enjoy your videos JIM
Good stuff! You taught more than magnetizing. How about inserting a PVC tube inside the electromagnet so that it will be easier to hold the cutting tool in the middle and avoid contacting the electromagnet?
When you magnetize something, how long does it remain a magnet? Until you demagnetize it or does it lose it's force over time? (I'm trying to find a cheap way to create small (eg, about 6"x6") flat magnetic surfaces to stick my metal craft dies to, to store them. (Either magnetize the die or the surface I'm sticking it to.) Advice appreciated!
It's not going to do anything that large. The magnetism will fade as the part gets bumped around. They make magnet rolls that you could glue to a surface. If that's not strong enough I believe Harbor Freight sells the long floor sweeper magnets with wheels. You could just remove the wheels and handle. www.harborfreight.com/17-inch-mini-magnetic-sweeper-98398.html
If you put something as simple as a 60 watt light bulb in series with the winding - whether the solenoid coil or the shaded pole motor, you have an automatic current limiter that will keep the coils from burning out. They may not work as quickly, but they won't burn out.
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If your going to get this from a microwave oven. Always take an insulated screw driver and short the capacitor out because if it has power stored in it from the high voltage transformer and you touch it with your hands it will kill you. That should be the first thing you do.
What are you talking about??? I own a jakemy jm-x2 Magnetizer/DEMAGNETIZER .made in China still running strong 💪 for almost 4 years now only paid $3 for it on eBay still looks and works like brand new and I still store it in its original packaging!
To be honest, a demagnetizer made from a shaded pole motor is probably going to last longer than the cheap ones being imported from China. Now, I just need to see if I still have any of these lying around.
Hah! I just burnt out a good one a nice fat one by leaving it on for too long dicking around feeling 60hz through the handle of the screw driver. I get mine out of microwave ovens for free. I didn't know these things burnt out like that but it lasted a good 2 to 3 mins before I seen a flash.
Are you using the fan motor from the microwave? I think I noticed the same motor in most microwaves for the fan. I'm going to use mine to make a fume extractor probably but the next microwave i come across i'll snatch it for a demagnetizer
@@schlomoshekelstein908 If you wanna build a fume extractor you best find you an industrial sized microwave instead. They got the same size transformer but there's an extra present under the hood. Instead of one fan you get 3 fans! Well actually 2 fans for there's a hamster wheel fan made by Samsung located at the top and they're much more suitable for fume extractor. I made one out of 2 and they're hella powerful because although they run one motor they got 2 hamster wheels. Beware of the high/low wires and capacitor start wires... you need em all
This isn't a reliable method to magnetize a tool. The magnetic field alternates with the AC line frequency (50/60Hz), alternatively (de)magnetizing the object N-S and S-N. The reason it works as a demagnetizer is this alternating magnetic field approaches zero as the object is drawn away from the still energized core, effectively leaving no net residual magnetism. If you leave an object in the core you'd need to switch off the primary current at the zero crossing of the AC cycle in order to retain maximum residual magnetization before the following opposite polarity cycles begins to reverse the effect of the prior cycle, gradually magneitizing it in the opposite pole orientation. So this approach is both hit & miss and of limited intensity. A far more effective way to magnetize an object is with a magnet of substantial strength (can be harvested from the magnetron of the microwave oven you're cannibalizing for the motor lamination frame), or the garage man's old standby of wrapping a 10~20 turn coil of wire around the to-be-magnetized object and giving the coil a quick high current pulse across the terminals of an automotive battery. Of course, try this at your own risk.
Tnx for the vid. In a pinch, I've magnetized a screwdriver or whatever by wrapping some wire (10-18 gauge) around the 'driver handle, then put the blade in the coil and touch it to the car or MC battery posts. In a flash (ar, ar, ar) - done! (To the "challenged" - don't do this, it is unsafe, and your mommy should have taught you better, tsk, tsk. If you are stupid, you might blow up the car, yourself, perhaps the neighborhood. There's gonna be sparks - no fuels or hydrogen from charging lead acid batteries. Yada)
