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Decent Demagnetiser?

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Chris TickTock04/09/2019 16:11:54
195 forum posts
5 photos

Hi, anyone recommend a decent brand of demagnetiser for smaller objects up to size of dial calipers.

Regards

Chris

Brian H04/09/2019 16:43:28
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1254 forum posts
96 photos

Eclipse.

Brian

Baz04/09/2019 16:46:36
265 forum posts

Plus one for Eclipse

Howard Lewis04/09/2019 16:57:32
2382 forum posts
2 photos

Depending upon the size, all that you need to demagnetise an item is to pass it through a fluctuating magnetc field.

Cassette recorder heads are demagnetised using a "wand" fed with low voltage AC.

Larger items are demagnetised by passing through a coil carrying an AC voltage.

So, it should be possible to make a demagnetiser, AS LONG AS YOU KNOW WHAT YOU ARE DOING.

I E Electrically safe,

No acessible terminals; earthed, or double insulated, and not taking excessive current likely to cause overheating and fire. The insulation should be adequate for the voltage applied. (Don't put 230Volts AC onto something insulated for 12 volts!)

For short term, intermittent use, an Induction motor, minus the rotor, used WITH CARE, might suffice, to pass small items through.

But switch off, and disconnect when not in use.

Now this should bring in folk who really are expert in electrics and such devices

Howard

Chris TickTock04/09/2019 17:00:38
195 forum posts
5 photos

And anyone got a safe relative easy build way to make a home made piece of kit. Seen several but some look very dangerous in terms of exposed electrical connections.

Chris

XD 35104/09/2019 17:46:06
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1352 forum posts
112 photos

Here is a home made unit for small tools that doesn’t use any power .

**LINK**

i use a degaussing wand that is designed for degaussing tv screens , bought it of ebay and is ok foe small tools like digital callipers.

Oldiron04/09/2019 18:20:17
286 forum posts
17 photos

I made one like this Demagnetiser from an old spin dryer motor many years ago. Many more video's on YouTube. Hope it helps.

Neil Wyatt04/09/2019 18:33:21
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Moderator
16641 forum posts
687 photos
75 articles

I've degaussed a TV by furiously waving a loudspeaker manget at it and slowly retreating. Took a couple ot tries to get it spot on.

Neil

BW05/09/2019 07:22:33
245 forum posts
40 photos

No electronics just 4 neodynium magnets. Described somewhere in popular mechanics - and a video of a similar one is here

https://www.homemadetools.net/forum/diy-demagnetising-tool-works-72881

 

Bill

Edited By BW on 05/09/2019 08:44:53

SillyOldDuffer05/09/2019 09:04:22
4769 forum posts
1011 photos
Posted by Chris TickTock on 04/09/2019 16:11:54:

Hi, anyone recommend a decent brand of demagnetiser for smaller objects up to size of dial calipers.

Regards

Chris

How about a Greiner Magnomatic Demagnetiser? Meant for watch and clock parts but also suitable for small tools.

Interesting that demagnetisers range in cost from waving an old loudspeaker magnet at the object for free up to professional devices like the Greiner costing a cool £1200.

Unless money is unlimited it pays to think about what the tool is to be used for and how often. My casual need to demagnetising the occasional screwdriver is easily met by carefully passing the object over a magnet in different directions until I manage to reduce the residual magnetism 'enough' by trial and error. An amateur clockmaker / watch-repairer would probably need a less labour intensive demagnetiser often enough to buy at least a simple AC demagnetiser. These still require the operator to manipulate items, but are easier to operate and get rid of most residual magnetism. Prices start from about £30.

Looking at the expensive Greiner, you get a far more sophisticated unit for your money. Its operation appears to be completely deskilled. The item to be demagnetised is dropped in the slot and the button pressed. I suspect an AC magnetic field is scanned several times from side to side along the item. When the first pass has finished, the operator presses the button again causing a second scan at 90° to the first. Expensive but no doubt results are quick and effective. The Greiner is ideal for a profitable repairer working against the clock. It's completely over the top for me and my screwdrivers unless I find one dirt cheap at a car-boot sale!

Doesn't help much, but as most of the cheaper units consist of little more than an AC coil and a timer, almost any of them will do for most purposes. For more serious use, what's your budget Chris?

Dave

Chris TickTock05/09/2019 09:56:08
195 forum posts
5 photos

Thanks Guys I have gone the eclipse route as the time I spend messing about might as well pay some money. It's second hand but if it works fine.

Regards to all poster I can see

Chris

John Pace05/09/2019 09:58:44
156 forum posts
156 photos

I made this unit from the drawings in Model engineer
designed by H.D. Bickley
Vol 167 no 3903 16 August-5 September 1991.
It works very well for small workshop items.

Johndemagnetiser.jpg

Andrew Johnston05/09/2019 10:48:27
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4876 forum posts
548 photos
Posted by Chris TickTock on 05/09/2019 09:56:08:

Regards to all poster I can see

surprise

Bit early to have someone on the ignore list?

Andrew

Chris TickTock05/09/2019 11:03:06
195 forum posts
5 photos
Posted by John Pace on 05/09/2019 09:58:44:

I made this unit from the drawings in Model engineer
designed by H.D. Bickley
Vol 167 no 3903 16 August-5 September 1991.
It works very well for small workshop items.

Johndemagnetiser.jpg

That looks a good project. Truth is when you enjoy making things its easy to get sidetracked in ancillary projects, sometimes its better just to spend the cash and conserve your time for the core objective.. Equally for most times a suitable magnet will do if used accordingly.

Useful post thanks John

chris

Ian S C05/09/2019 11:04:15
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7447 forum posts
230 photos

I made a demagnetizer using a primary coil from the transform,er from a microwave oven, powered by a 12v transformer from a low voltage electric blanket. The coil is in the ply box on the left.

Ian S C

dsc00682 (640x480).jpg

Bandersnatch05/09/2019 18:31:06
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1261 forum posts
40 photos

They used to sell demagnitisers for VCR cassettes. There ought to be a few of those going spare still.

Russell Eberhardt05/09/2019 19:33:55
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2487 forum posts
85 photos

I made a very crude demagnetiser for my three jaw chuck jaws using an old instant soldering iron:

demag.jpg

It took five minutes to make and did the job. Much quicker than buying one!

Russell

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