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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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Judging by how hard it tugged at my tools I don't think I'd want to put a watch near to mine.  Anyway I've ordered some more magnets and I'm going to build a slicker version now I know it works, with

1 hour ago, aesmith said:

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

OzFcsII.jpg

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I made this out of magnets, epoxy resin and some stuff I had lying around. I had seen a YT video of a homemade version that worked. Essentially you spin the magnets, hold the tool near the demagnetiser then slowly withdraw the tool from the field.

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It works!  I didn't make anything as posh as yours. I used 3/8" plywood, around 2 1/2" square, a 1/4" both through the middle as a mandrel (is that the right word) and four 10mm holes at 90 deg intervals around 20mm from the centre, the magnets a push fit into the holes.  I say around because none of this was measured.  I span it in a cordless drill and it successfully demagnetised two of my three pairs of tweezers, my springbar tool and some screwdrivers.  The third pair of tweezer remained very slightly magnetic even after several goes.

It's a weird feeling, the magnets tugging at the tool, and strangely it started to unscrew the tip of the springbar tool.

Disadvantage of my lash up is that it's not a flat flush face like yours so the tool has to be held close but not touching.  An 1/8" or so plastic face would be an improvement.

How close are your magnets to the surface of your assembly?

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14 minutes ago, aesmith said:

It works!  I didn't make anything as posh as yours. I used 3/8" plywood, around 2 1/2" square, a 1/4" both through the middle as a mandrel (is that the right word) and four 10mm holes at 90 deg intervals around 20mm from the centre, the magnets a push fit into the holes.  I say around because none of this was measured.  I span it in a cordless drill and it successfully demagnetised two of my three pairs of tweezers, my springbar tool and some screwdrivers.  The third pair of tweezer remained very slightly magnetic even after several goes.

It's a weird feeling, the magnets tugging at the tool, and strangely it started to unscrew the tip of the springbar tool.

Disadvantage of my lash up is that it's not a flat flush face like yours so the tool has to be held close but not touching.  An 1/8" or so plastic face would be an improvement.

How close are your magnets to the surface of your assembly?

couple of mm, but the shaft is not central so the magnets oscillate slightly, I tried with my mini seiko diver (i believe it may be magnetised as a cause of its wild time keeping).

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We used to just rub a magnet on a screwdriver shaft to demagnetise it.

I can't remember which way but something like up the length of the shaft to magnetise and rotate the shaft against a static magnet to de-magnetise or vice-versa.

Try it, it works.

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17 hours ago, nursegladys said:

I tried with my mini seiko diver (i believe it may be magnetised as a cause of its wild time keeping).

Judging by how hard it tugged at my tools I don't think I'd want to put a watch near to mine.  Anyway I've ordered some more magnets and I'm going to build a slicker version now I know it works, with a flush face of some sort so I can start with the items right up against it if I wish.   Maybe six magnets, but I also think the number might not matter, just need to spin faster if there are fewer magnets.

Edit I was looking for inherently non-magnetic tweezers on Ebay, and was surprised to find some actually advertised as magnetic, so clearly it's a good thing for some people.

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I was just coming to see if @nursegladys had had any success with his demagnetising disc.  I haven't done mine yet as I've been elsewhere for 10 days, but I bought some little magnets (decided it would be quicker than trying to find the ones I have somewhere) with countersunk holes on one side, thinking it would be easy to tell which pole was which and I could screw them easily onto a piece of timber in a circle - with a large screw with the head ground off for the mandrel, on the opposite side.

My sister and I have been at our parents' house doing some more clearing over Easter and she said she'd wanted help with something and suddenly missed Dad very badly and I said the same and cited this demagnetising tool I was planning to make - he would almost certainly have had one and absolutely certainly would have known how to make one.  I was describing to my sister how I was going to make it and that I'd have a dig in the garage for a suitable piece of wood while I was there. 

She was going though papers on a shelf and passing things to me.  She asked me how big was this thing going to be and how much wood did I need.  I said "ideally a round of about 4 or 5" in diameter, so a scrap will do" and she said "would this do?" and passed me a 90mm diameter circle of plywood, nestled amongst his scrap paper on a shelf.

He still somehow managed to help me from the grave.  She then said "I could really use an envelope stuffed with £50 notes" but it didn't materialise.

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1 minute ago, BooJewels said:

I was just coming to see if @nursegladys had had any success with his demagnetising disc.  I haven't done mine yet as I've been elsewhere for 10 days, but I bought some little magnets (decided it would be quicker than trying to find the ones I have somewhere) with countersunk holes on one side, thinking it would be easy to tell which pole was which and I could screw them easily onto a piece of timber in a circle - with a large screw with the head ground off for the mandrel, on the opposite side.

My sister and I have been at our parents' house doing some more clearing over Easter and she said she'd wanted help with something and suddenly missed Dad very badly and I said the same and cited this demagnetising tool I was planning to make - he would almost certainly have had one and absolutely certainly would have known how to make one.  I was describing to my sister how I was going to make it and that I'd have a dig in the garage for a suitable piece of wood while I was there. 

She was going though papers on a shelf and passing things to me.  She asked me how big was this thing going to be and how much wood did I need.  I said "ideally a round of about 4 or 5" in diameter, so a scrap will do" and she said "would this do?" and passed me a 90mm diameter circle of plywood, nestled amongst his scrap paper on a shelf.

He still somehow managed to help me from the grave.  She then said "I could really use an envelope stuffed with £50 notes" but it didn't materialise.

enjoyable read, thank you, sorry for your loss.

I make things because I find great satisfaction in doing so [also I'm a tight arsed sod], especially if they work, and yes it did work, the watch is now running to less than 10 secs a day.

I did make another from a large Smartie tube bottom, but this time I used a glue gun, first to stick the magnets to the base so they don't attract to each other and keep their spacing, once that was dry I filled the cap with the shaft in place, it has been difficult to keep the shaft vertical, but it doesn't need to be perfect

@BooJewels

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5 hours ago, nursegladys said:

I make things because I find great satisfaction in doing so [also I'm a tight arsed sod], especially if they work, and yes it did work, the watch is now running to less than 10 secs a day.

I make jewellery for my living and making my own tools and equipment is something I do whenever I can - for pretty much the same reasons you cite.

Delighted to hear that it worked for you.  I have a couple of cheaply bought watches from a lot where there was one I specifically wanted and they're running very fast and someone suggested that they might be magnetised - they certainly cause a compass to noticeably move  So it's worth a fiver and more importantly, another good lesson, to find out.

Thanks for the kind words - it all feels rather grubby going through someone's stuff and divvying it up, but I'm sure that my Dad would develop a wry smile at the sight of me using his tools to make things and effect repairs, upgrades etc.  My sister was going though a little cupboard and yelled "I've found Dad's porn stash".  It was a pile of catalogues for Proxxon, Silverline, Tandy, Screwfix, Maplins etc. etc.  :laugh:

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Just a quick update, I was dressing the tips of a couple of screwdrivers and tweezers yesterday, and of course most became magnetised in the process.  Since I'd put the cordless drill away, I tried twirling the demagnetiser between my fingers and found that worked perfectly well.  I've just received my new smaller round magnets so I think when I replace my rough first draft I'll use a smaller diameter shaft specifically with handheld use in mind.  Maybe six magnets, compared to the four in my first one.

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I was wondering about the number of magnets and whether that and the distance between them made any difference to the efficacy of the tool. 

As I bought a batch of 20, I thought that with a 70mm diameter circle for their centres, using 10 at 10mm diameter would put their centres 22mm apart, so about the same amount of magnet and space.   That seemed even and efficient to me, but I don't know how much difference it makes, or what impact the speed of spin makes either.

I suppose any number of magnets above 2 would work - maybe the more you have, the slower it can be spun?

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2 hours ago, aesmith said:

Just a quick update, I was dressing the tips of a couple of screwdrivers and tweezers yesterday, and of course most became magnetised in the process.  Since I'd put the cordless drill away, I tried twirling the demagnetiser between my fingers and found that worked perfectly well.  I've just received my new smaller round magnets so I think when I replace my rough first draft I'll use a smaller diameter shaft specifically with handheld use in mind.  Maybe six magnets, compared to the four in my first one.

 

2 hours ago, BooJewels said:

I was wondering about the number of magnets and whether that and the distance between them made any difference to the efficacy of the tool. 

As I bought a batch of 20, I thought that with a 70mm diameter circle for their centres, using 10 at 10mm diameter would put their centres 22mm apart, so about the same amount of magnet and space.   That seemed even and efficient to me, but I don't know how much difference it makes, or what impact the speed of spin makes either.

I suppose any number of magnets above 2 would work - maybe the more you have, the slower it can be spun?

OK, so I've just googled magnetic spin vortex :sign_what:essentially the north and south poles produce a magnetic donut shaped field that spin opposite each other.........and that's where I lost the plot with regards to the idea of rotating magnets to demagnetise objects :sign_question:

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7 minutes ago, BooJewels said:

I know how you feel @nursegladys - my own son is a Geophysicist and an expert in magnetism - it's his field, so to speak.  Unfortunately for me, his method for demagnetising is to heat things to 1200°C within a pulsed vacuum, or something.  So that didn't help me much either.

Degaussing - Wikipedia

@BooJewelsI found this, mainly regarding ships, but interesting none the less.

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The idea is to apply a reversing magnetic field, so I don't think it's the spin itself that does it, it's the fact that the tool sees the magnetic field alternating between two polarities.  "Normal" demagnetiser use the mains to create a field that switches back and forth 50 times a second.  To exactly replicate that with my four magnet rig I'd need to spin it at 1500 rpm, but my test twiddling with my fingers suggests it doesn't need to be that fast.

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1 hour ago, aesmith said:

The idea is to apply a reversing magnetic field, so I don't think it's the spin itself that does it, it's the fact that the tool sees the magnetic field alternating between two polarities.  "Normal" demagnetiser use the mains to create a field that switches back and forth 50 times a second.  To exactly replicate that with my four magnet rig I'd need to spin it at 1500 rpm, but my test twiddling with my fingers suggests it doesn't need to be that fast.

@aesmith i think a power drill to spin it, whilst holding and drawing away with the tool is sufficient, not sure how long one would have to spin it by hand for it to work?

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24 minutes ago, nursegladys said:

@aesmith i think a power drill to spin it, whilst holding and drawing away with the tool is sufficient, not sure how long one would have to spin it by hand for it to work?

Needs some more testing and practice I think, in particular since magnetic fields fall off really quickly with distance I suspect the movement away needs to be very slow for the first inch or so.  I have one pair of tweezers which are not stainless and are very prone to magnetisation, and which I couldn't completely demagnetise, those will be the ones to test with.

How are you testing for magnetism before and after?  I was using metal dust picked up from under the vice in the garage but it's just occurred to me that the dust itself may be magnetic as well.

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5 minutes ago, aesmith said:

Needs some more testing and practice I think, in particular since magnetic fields fall off really quickly with distance I suspect the movement away needs to be very slow for the first inch or so.  I have one pair of tweezers which are not stainless and are very prone to magnetisation, and which I couldn't completely demagnetise, those will be the ones to test with.

How are you testing for magnetism before and after?  I was using metal dust picked up from under the vice in the garage but it's just occurred to me that the dust itself may be magnetic as well.

I didn't test it, it was running 9-10 minutes out each day, demagnetised it, now running within 10 secs a day without regulation. I don't know what the test is for magnetised tools etc.

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I searched to see how to test if a watch was magnetised and something I read said to hold the item near a compass and see how far the hand moved - 30 degrees or more suggested the item was magnetised.  The two watches that I think may be, moved the compass needle 30 or 40 degrees.  They're both running fast - like 5 minutes an hour or more.

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You don't need the BB code, just click the 'Insert image from URL' button in the bottom right of the posting window and put the URL in there and it embeds the image. 

But it might be a Flickr thing, they've made so many changes that I don't know if they'll allow remote linking of images now, unless you have a pro account.

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1 hour ago, BooJewels said:

You don't need the BB code, just click the 'Insert image from URL' button in the bottom right of the posting window and put the URL in there and it embeds the image. 

But it might be a Flickr thing, they've made so many changes that I don't know if they'll allow remote linking of images now, unless you have a pro account.

I use Imgur, upload image to their site, copy and paste from the "direct link" on right of image, click "insert image from URL", and Bob is someone's uncle.

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Here we go ...

 

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Carbon steel tweezers before, tested by dipping into the metal dust ...

TA62BZx.png

And cleaning the dust off, a quick twirl of the thing, then another dip.  I can get them a little better, but not completely zeroed out as I can with the stainless tweezers ...

SQgjP1a.jpg

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