DIY Demagnetising tool that works

[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!