A 3D Printed Passive Demagnetiser using Neodymium magnets

I saw a recent post on the HomeMadeTools.net site from Tony Foale about using Neodymium magnets in a rotating holder to act as a demagnetiser. 

Tony made the holder from aluminium but from my point of view with Fusion and 3D printing facilities the idea lent itself to be run as a 3D print.  The finished device can be held in a lathe or drill press chuck using the central boss.  The boss does not have to be rigidly clamped as the magnets will grab and locate the assembly up to the chuck.   The magnets are very strong so be very careful as you bring the object to be demagnetised up to the lower surface or it will also get ‘grabbed’. 

Attached is a ZIP file containing the Fusion 360 file.   This is designed to take 10mm diameter magnets which will be a tight push into the mounting holes.   I used 10mm long magnets but smaller ones will probably work just as well. The magnet mounting holes have a 1mm thickness bottom surface.   The magnets need to be inserted with the alternating orientation as shown.  Tony made a circular ‘keeper’ for the bottom surface from a steel disc.  This reduces the attraction to swarf.   The ZIP file also contains a simple lid to fit over the top side to protect the holes from accumulating magnetic swarf.

Screen shot of the demagnetiser fusion file
Pictorial screenshot view from Fusion 360 of the demagnetiser 3D model

ZIP file download is on the link below and contains the body and lid as a Fusion file and as separate STEP files  – demagnetiser disc body and lid

A closing thought (which I haven’t tried …) but if all the magnets were in the disc the same way round would this act as a magnetiser to save having to stroke the item with a magnet ?

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