That's great! I only wish it was my idea. I made a much more elegant version here kzfaq.info/get/bejne/e91kddqKueCnlWw.html I use mine regularly and it hasn't let me down once. Regards, Mark

Good tip, I've got one of those guns.👍

I still use the same procedure today

​Yeah I got three or four if I can find one. The Weller 325 watt would work. I made a copper coil around the two hook up points. I wanted to make a solder pot but it didn't get hot enough to heat the barrel plug. I wanted to fill with solder. A torch works but it's not for indoor work. 73​@@fredfarnackle5455

sOME TIME THOSE VERSIONS WORK IN A STRANGE WAY, they dont demag completly. If you had a watch repair shop , fixing watches that cost 30.000 bucks, for sure you wouldnt use your version.

Who would have thought it was so simple? I had previously struggled with the prospect of having to modify a mains operated transformer for an electromagnetic solution. I hate the idea of having to have live voltage to do the job so the magneto/mechanical solution was gold. Regards, Preso

Yes, and it's entirely mechanical. No batteries required!

Jose, the other good thing is that you can put the demag tool in a power drill and pass it over larger parts that aren't easy to move around. It works great for me.

Rodney. I only wish I could claim it was my idea. I think I saw this on the Home Shop Machinist forum. However, it's so simple and it works. Everyone should have one! Regards, Mark

That's great. Mine gets a regular workout in the drill press. Regards, Mark

I have seen that too but it never worked for me. It would magnetise a tool OK but I never had any success completely demagnetising a tool with it. I used my rotary demag tool today to demagnetise a centre drill that was holding chips. It just works every time. Regards, Mark

You should probably watch the latest iteration of this tool as well. kzfaq.info/get/bejne/e91kddqKueCnlWw.html It has a better explanation of how to fit the magnets. Regards, Mark

Thanks for the technical explanation. This was definitely a "gut feeling" build. Magnetism is a sort of devil magic as far as I'm concerned! 😁

That's really interesting. We had a severe thunderstorm that killed a quartz clock movement. It stopped at exactly the same time as a lightning strike near our house. I guess those clock movements use some sort of magnetic field to move the mechanism. It was battery powered and not connected to the mains so it wasn't a power surge that did the damage. Regards, Mark

Thanks Mart. I was also surprised when I made the first version of this tool. It seemed unlikely that such a simple concept would work as well as it does. You could easily make one of these with a 3D printer. Regards, Mark

Ahh, I still remember Radio Shack. It always had a distinctive smell in those shops. That "Realistic" brand name was on everything they sold from what I recall. I did start off with the idea of modifying an old transformer to make something similar but the instructions I read about how to carry out the modifications started to get a bit scary with electricity and all. But if you could buy something off the shelf that works it would be worth it. I still use my rotary demag tool. It is stuck to the side of my drill press and I use it often. It still seems like magic when it works. Regards, Mark

I have seen that happen when I quartz watch is placed close to a heavy duty spot welder. The magnetic field around the copper arms will speed up the watch. It didn't seem to harm the mechanism but you are correct that if you don't notice it schedules will suffer! Regards, Mark

Please do. It's a low tech and utterly reliable way of demagnetising things. I did another video showing how it was made here. kzfaq.info/get/bejne/e91kddqKueCnlWw.html Regards, Mark

Thanks Dave. It certainly seems to work but it was only after finishing it I started to second guess myself but as you point out the steel must be doing it's devil magic somehow.

John. Glad you found it useful. I have to demag my calipers regularly. I still don't know why tools of all types gradually become magnetic. It's a mystery!

Hello again Mark, I have also noticed on my scribe that it also becomes a little magnetic after a touch up on the grinder, that is also frustrating when marking something out with a ball of fuzz on the end. Cheers from John, Australia.

I have had the same problem and it drives me mad too. The tool doesn't seem to affect the electronics in the set of Sylvac digital calipers I was using. I only place the open ends of the jaws under the rotating magnets. Regards, Mark

I am not sure how small you could make a rotary demagnetising tool of this type. I guess it depends on whether you can source some very small neodymium magnets. I have seen some small cylindrical types (1mm diameter and 10mm long) and you only need two if you can rotate them around a central axis. Having four just means that you don't need to spin them quite as fast to get an oscillating magnetic field. The key is to ensure that you slowly withdraw the tool from the demagnetiser or vice versa so that the oscillating field decays slowly. I would just 3D print a simple holder and try it out to see if it works on a piece of magnetised scrap about the size of a tape head? Regards, Mark

NO, WHAT IS BRILLIANT IS, to BUY A DEMAGNETIZER TOOL. HAD ONE IN A SHOP AND IT WAS VERY USEFULL. JUST PUT THE ITEM ON THE DEVICE AND PRESS BUTTON ...ET VOILÁ-. AMAZING ISNT IT?

The poles of the magnets just need to be opposed. So if you have four magnets, the ones at 12 O'clock and 6 O'clock will have, say, south pole down and the ones at 3 O'clock and 9 O'clock will have north pole down. You can use any even number of magnets in an array. I have seen some versions with up to 12 magnets. The greater the number of magnets, the more pulses you will get for each revolution of the tool. Regards, Mark

You won't regret it. It's certainly one of the tools that I find to be super useful and it's so simple to use. Regards, Mark

@@Preso58 Morning brother (4:35am here where I live). I surely agree that sometimes a tool should be magnetic but many times not, like a milling cutter. I just have to find small magnets and I will be on your level. Have a great day.

I have made three of these things and they work great. They are so simple and much safer than the doctored transformer type. I only realised after shooting all the video that I accidently took the screwdriver out of the frame during the crucial shot and as a result I had been accused of doing a switch and faking the results. If I were charging people money I guess there would be a case to answer but people are free to take it on face value. Regards, Mark

It's so simple and yet really effective. You can also mount it in a cordless drill and just take it to a part which may not be able to be removed. Good luck with it! Regards, Preso

No, that is a surprise. I hope it works for you. Regards, Mark

John, I find that tools like punches, scribers and rules tend to pick up a magnetic field over several months. I have a couple of those magnetic tool holders above the bench which will gradually magnetise those items near or on it. However, the demag tool is so easy and quick to use that I can pass the tools over it while it is in my lathe or my drill press quite easily. I really should mount it permanently on one of my double ended grinders! Welders will create a magnetic field around the ground and electrode holder cables because of the current in the circuit. If you have been doing any grinding, the metal dust will be attracted to the area around the cables. Regards, Mark

I have used that demag tool on my Mitutoyo calipers and it doesn't seem to affect the electronics or the read head so I think it would be fine on a watch. You might need to put something like soft felt on the cap over the magnets. Parts are initially attracted to the cap quite strongly and it might scratch the watch. My drill press is somewhat noisy because I fitted a "pull gear" to the motor shaft. It is a reduction gearbox which uses planetary gears and they tend to rattle when it is in direct drive (nearly all the time). Before I fitted it I had a poly vee step pulley drive and it was super quiet. The VFD also adds to the noisiness too. Regards, Mark

@@Preso58 report: made it. used it on a1969 longines automatic watch that was running well but extremely fast (the sign of magnetization) and after two tries only temporary success. After a third more extensive round of passes on both top and bottom of case- success. in fact, the watch came right back to the time it had been keeping a few months before it went off the rails. I have a feeling it must had met a random neomydeum refrigerator magnet at some point

Kevin, I did actually make two more but I gave them away, one to a friend and one as a subscriber draw. However I don't plan to manufacture them. They are extremely simple to make and don't need to be terribly accurate or made from metal. If you have access to a 3D printer it could be used to make the body and the spindle. You could actually embed the magnets during the printing process. Even something made from wood with the magnets stuck on with epoxy would work fine. Here is the link to the build video for a better finished design. kzfaq.info/get/bejne/e91kddqKueCnlWw.html

Yes. You are correct regarding the polarity of the magnets. They should alternate North South. I did use neodymium magnets. They were 10mm diameter and 2.5mm thick but you could use other sizes or shapes. I am pretty sure you could make the body of the tool completely from plastic or wood even and it would still work.

I did make another version with full detail on that build. kzfaq.info/get/bejne/e91kddqKueCnlWw.html Regards, Mark

I have great success in magnetising tools but getting them demagnetised is more complex. Especially if it's something like your digital calliper. Nothing is more annoying than having little chips sticking to the measuring surfaces and since there are two tips it's not quite so easy to do it with a single magnet. This tool does work well on larger tools or tools with odd shapes. Regards, Mark

@@Preso58 Even my drillbits get magnetized somehow, it takes no effort lol, really annoying indeed! I guess the single magnet trick is only good for simple parts.

Ben, unfortunately there's nothing to oil. Those Taiwanese drill presses have sealed ball bearings in the spindle. I bought the machine second hand and it's possible that the bearings are not the best. I converted the vee belt drive to a poly vee drive and the belt (being quite a lot thinner than a standard vee belt) does tend to flap around a bit. Also I have a three phase motor and a VFD fitted to the drill so it contributes a bit to the noise as well. Regards, Mark

I think that vfd is what people are hearing

That tool is only for demagnetising parts. You can deliberately magnetise a non magnetised part by taking a rod type magnet and passing one end or pole repeatedly down the length of the part. You must stroke the pole of the magnet in one direction only and lift the magnet well clear as you go back to your starting point. You usually only need to do about 6 or 8 passes and it will pick up a good magnetic field. It's useful to be able to magnetise a screwdriver tip temporarily so you can pick up a steel screw for assembly and then use the demgnetising tool when you are done to remove the stray field. As for magnets with weak magnetic fields you are probably not going to be able to do much about that. You may be able to partially restore some magnetism if you have a stronger magnet and use the technique that I suggested for tools. Regards, Mark

I had the idea that you could just about totally 3D print all the parts (except the magnets). It seems such an unlikely solution and it can be as simple or complex as you want to make it. Regards, Mark

Did you have a lightning strike nearby? I have heard that this can cause large metal objects to become magnetised. I also recall that many large steel ships would become magnetic during their construction due to them being stationary and close to the earth's magnetic field. Regards, Mark

@@Preso58 no sir. Used to have some magnets here and there on and around tools/bench. They were removed over a year ago unfortunately they still stickin around.

I hope you found it useful, Regards, Preso

The process should be scaleable but man, you would need some big magnets!

@@Preso58 I wonder if could try your contraption "on the surface"...

I made another version of this tool for a giveaway. kzfaq.info/get/bejne/e91kddqKueCnlWw.html I show the entire process of making this tool including how to arrange the poles of the magnets. Regards, Mark

I generally run it at around 400 to 600 rpm but it's not critical. There are 2 pair of magnets with opposing poles so at 400 rpm you get 800 alternating magnetic pulses per minute. The most important thing is that you slowly withdraw the tool from the magnetic field which extends quite a way from the centre of the tool. I usually take it straight out for about 300mm which seems to completely eliminate any residual magnetism. I did a whole heap of punches, allen keys and screwdrivers just yesterday since they were all gathering fuzz of metal dust on the working ends. Regards, Mark Presling

Sure, you can get my email address from the "about" page on my channel. kzfaq.info/love/YfDX1Gno-PuJ-QWLbH09Sgabout?view_as=subscriber

Yeah, that bugger Darwin will take care of the unwary!

Refrigerator magnets aren’t?

Not really. It is just a case of alternating the magnetic poles enough times to neutralise the residual magnetic field in the magnetised part. If you doubled the number of magnets you could achieve the same result with less revolutions but it would probably still take the same amount of time to do the job. Regards, Mark

@@Preso58 I used 6061 aluminium alloy for the job, and used 8 magnets. Reason why is none of my drill spin at a high speed. Waiting on the 10mm magnets to be delivered will let you know how the alloy performs. Thanks for your prompt reply.

@@Preso58 I built one using 8 x 10mm magnets and works very well. Thank you for sharing!

Assuming it's mechanical?

It's a Citizen Eco Drive which I believe is a quartz watch with a solar power source that doesn't require a battery. However it does have a capacitor to store the electrical charge. I liked the watch because you never need to take it to a jeweller to have a battery replacement. I guess the thing you are wanting to know is whether it is influenced by the magnetic field of the demagnetising tool. Short answer is that I didn't notice it gaining or losing time. I do know that strong magnetic fields can affect quartz watches though. We used to have a large spot welder at the school where I used to teach and if you held a quartz watch up against the electrodes and powered up the welder you could see the watch run at about 10X speed due to the magnetic field around the copper arms of the welder. It used to amuse the students no end! Regards, Mark

If it is magnetised it should work. However I am not a watchmaker and it could be that some parts of a particular watch are sensitive to magnetic fields. Also, most watches are stainless steel and those grades are generally non magnetic. Some parts like the pins that hold the bracelet together might be able to be magnetised. Regards, Mark

@@Preso58 Yay, It has worked so far. I have a gold filled Omega that is said can become magnetized causing it to run fast. I just used a binder clip to hold 2 (2"L X 1/2" W) magnets with 1 negative and 1 positive facing up. I then held my watch and made circular motion above the magnets while I slowly moved the watch away from the magnets. I repeated this about 4 times. Thank you for the diy that saved me a trip to the watch repair shop! I really appreciate it!

@@kjbigsful That's great! If you know anyone who owns a 3D printer you can make a simple version that can be fitted to a cordless drill. Regards, Mark

There must be plenty of opportunity for magnetic fields to form in and around machinery. Welders are probably a major culprit. I have seen magnetic field line patterns around the welding leads on my steel bench after grinding steel. I also have magnetic welding clamps and lots of neodymium magnets lying around which probably all contribute to the problem. Regards, Mark

Good idea. It does attract a lot of rubbish but the plastic cap allows most of it to be wiped off fairly easily. Regards, Mark

Scott, I was looking to build a demag tool which I had seen described on a forum and it involved a modified mains voltage transformer. You were supposed to cut into the iron laminations but the whole affair seemed to be fairly dangerous. Some one described the rotary tool on the same forum (it's not my idea) and so far it has never failed (or killed me). Regards, Mark

I know. I was absolutely amazed when it worked!

Trust me, I tried that and just about every other trick I knew. The thing is that when the tap broke off it was bottomed out in a fairly shallow hole so it was fully torqued down and even if I could have gotten a grip on it there was not sufficient leverage to back it out again. It was either EDM or scrap the part. Regards, Mark

Well, if you think it will work, go for it. It can't do any harm. Regards, Mark

With respect, that's a bit unfair. I am not selling this tool nor do I make any money out of my KZfaq videos. I presented the video in good faith and despite what you may think, the tool does work and I use it regularly in my workshop. Regards, Mark Presling

Interestingly, I have never thought about doing it in reverse. My understanding is that you can effectively magnetise a tool by stoking a magnet pole along the length of the tool (like a screwdriver) and then moving the magnet pole away and repeating the same stroking movement a number of times. The demag tool works by pulsing the magnetising process and then decaying the process until it is neutralised. If you want to deliberately magnetise something you would need to do the same action in reverse (i.e., move the tool closer) and probably at low speed. Regards, Mark

COOL! I'm glad it worked for you. There's nothing worse than a scriber that picks up swarf all the time. I have also put files down on the bench only to see a little halo of steel dust form around them. Creepy!