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Demagnetising Small Tools


aesmith
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Hi,

I found to my dismay that it seems all my small tools have become magnetised for some unknown reason.  I see you can get quite cheap things that claim to demagnetise, looking like plastic blocks with slots, like this ...

https://www.ebay.co.uk/itm/Magnetiser-Demagnetiser-Tool-Mini-Toolbox-Essential-Screws-Screwdriver-Repair/114283439821?hash=item1a9bd2e6cd:g:OnQAAOSwGQlfAMjj

Is anything like that any use?  If not then what would be recommended, to demagnetise small tools not necessarily anything you'd put a watch anywhere near?

Thanks, TS

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This is my effort and the jury's out as to whether it is working or not.  Having made it, I now had a couple of screwdrivers that were magnetised.  One stubbonly remains so, the other lost its magnetism with one offering up to the tool.  I haven't checked by how much yet, but the two watches that were running fast were still doing so after many visits to the disc. in various orientations - I don't think it was to the same degree, in the 2 hours they'd been running by the time I went to bed, but they certainly weren't within wearable tolerances yet. 

I spun the device in a modified cordless drill (runs on mains, but my Dad had modified it to start very slowly for me, as I use it to coil and twist wire), using a large screw that I ground the head off, as a shaft - just because it made it easy to just screw it into the timber.  It meant that I could easily try spinning it at different speeds.  The magnets are 10mm x 3mm thick and are fixed in a circle of 70mm at their centres.

@nursegladys My own thinking had been that to create an alternating field, you'd perhaps need some space between the magnets, so that their fields didn't overlap, hence the size and spacing I went with - but that was only a feeling/hunch - not based on science.  I wonder if bringing them to a smaller diameter circle, with less space between them might work better?  I actually hold the items over the ring of magnets, to one side, not the centre of the disc.

DemagFront_sm.jpg

 

DemagBack_sm.jpg

Edited by BooJewels
Just to clarify my wording better
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1 hour ago, BooJewels said:

This is my effort and the jury's out as to whether it is working or not.  Having made it, I now had a couple of screwdrivers that were magnetised.  One stubbonly remains so, the other lost its magnetism with one offering up to the tool.  I haven't checked by how much yet, but the two watches that were running fast were still doing so after many visits to the disc. in various orientations - I don't think it was to the same degree, in the 2 hours they'd been running by the time I went to bed, but they certainly weren't within wearable tolerances yet. 

I spun the device in a modified cordless drill (runs on mains, but my Dad had modified it to start very slowly for me, as I use it to coil and twist wire), using a large screw that I ground the head off, as a shaft - just because it made it easy to just screw it into the timber.  It meant that I could easily try spinning it at different speeds.  The magnets are 10mm x 3mm thick and are fixed in a circle of 70mm at their centres.

@nursegladys My own thinking had been that to create an alternating field, you'd perhaps need some space between the magnets, so that their fields didn't overlap, hence the size and spacing I went with - but that was only a feeling/hunch - not based on science.  I wonder if bringing them to a smaller diameter circle, with less space between them might work better?  I actually hold the items over the ring of magnets, to one side, not the centre of the disc.

DemagFront_sm.jpg

 

DemagBack_sm.jpg

these are mine Heath Robinson Mk 13 and Mk 14 (my numbering system for my creations over the years)

.The purple one has 6 magnets, arranged circular and touching.

R5OJUMu.jpg

I have just tested the purple one and it works :clap:

Edited by nursegladys
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I'm wondering if I've gone too large with mine.  

My original idea was to use a disc, but hold the item to the edge, so that only one row of magnets was in the 'active zone' as it were, so as the disc spun you'd get a pulsing magnetic field as the magnets - with their spaces between - passed the object, thus:

North pole on > off > south pole on > off > north pole on > off > south pole on etc. 

You'd have to spin it fast enough, so that at no time was the object just exposed to a positive magnetic field, thereby re-magnetising the object.  Hence setting it spinning before introducing the object.  It feels to me that if it were too small, there would be too much room for error in lining up the poles with the object and not favouring one side over another.

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28 minutes ago, BooJewels said:

I'm wondering if I've gone too large with mine.  

My original idea was to use a disc, but hold the item to the edge, so that only one row of magnets was in the 'active zone' as it were, so as the disc spun you'd get a pulsing magnetic field as the magnets - with their spaces between - passed the object, thus:

North pole on > off > south pole on > off > north pole on > off > south pole on etc. 

You'd have to spin it fast enough, so that at no time was the object just exposed to a positive magnetic field, thereby re-magnetising the object.  Hence setting it spinning before introducing the object.  It feels to me that if it were too small, there would be too much room for error in lining up the poles with the object and not favouring one side over another.

I don't think it matters that it's super accurate, it would seem that a rough estimation will suffice its the alternating fields you are after. I also don't think it matters if they are touching or not. I've seen videos of both methods that work, but none as wide apart as yours.

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I'm such a dufus - mine is actually working - pretty well, as it happens.  The screwdriver that persisted with its magnetism - does in fact have a blooming magnet in it.  It was only when I went to take the bit out to try and demagnetise it without the handle that it sits in that the penny dropped.  Sorry, I qualify for the idiot of the day award.  I'd been thinking it was a little ball catch - never occurred to me that it was magnetic.

I tried it with a number of tools that either were already magnetised, or that I made so and it worked 100% on them all.  So whilst it might not look like others documented, it does actually seem to work.  Just a variation on a theme.

As for the watches I hoped it might sort, I think they're just buggered anyway - it did improve one of them - it's only 40 minutes fast over 14 hours, which is better than it was, but not wearable.  They're not of any importance, just residual extras from a cheap job lot I bought, of which I already have 3 watches I can use, incliding a pristine Seiko 5.  I was just curious to see if it might help as one of them is a 1970s Avia hand wind with a pretty face and a seconds sub dial.

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49 minutes ago, BooJewels said:

I'm such a dufus - mine is actually working - pretty well, as it happens.  The screwdriver that persisted with its magnetism - does in fact have a blooming magnet in it.  It was only when I went to take the bit out to try and demagnetise it without the handle that it sits in that the penny dropped.  Sorry, I qualify for the idiot of the day award.  I'd been thinking it was a little ball catch - never occurred to me that it was magnetic.

I tried it with a number of tools that either were already magnetised, or that I made so and it worked 100% on them all.  So whilst it might not look like others documented, it does actually seem to work.  Just a variation on a theme.

As for the watches I hoped it might sort, I think they're just buggered anyway - it did improve one of them - it's only 40 minutes fast over 14 hours, which is better than it was, but not wearable.  They're not of any importance, just residual extras from a cheap job lot I bought, of which I already have 3 watches I can use, incliding a pristine Seiko 5.  I was just curious to see if it might help as one of them is a 1970s Avia hand wind with a pretty face and a seconds sub dial.

:rofl: never mind, live and learn. Not so much a Darwin but Gilbert award, never a Planck :thumbs_up: glad it's working for you.

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