De-magnetizing a Screwdriver

My screwdrivers have inadvertently become magnetized.
Whilst handy at times (for picking up screws), it is of course also a no-no for electronics.

What method could I use to demagnetize them?

Do you know the principle used in that device?

I do have quite a strong magnet with a hole in the centre (somewhere) and was wondering if by poking the screwdriver through the hole I could magnetize/demagnetize by poking from different sides (poles).

No, you have to gradually withdraw the screwdriver from an AC electromagnet. A strong magnet will
just make the screwdriver strongly magnetized. The gradual movement to weaker and weaker AC field
allows the magnetization to spiral around the hysteresis curve inwards towards the origin.

The alternative is raising the screwdriver temperature above the Curie point, but that will lose its
hardness/temper and melt the handle.

Pass the shaft a few times between the posts of a soldering gun while it's operating. Guaranteed to work.

Jon

Better still add a coil of substantial wire like this:

I've used that to demagnetise more substantial tools than just screwdrivers. Just be sure to take the screwdriver well away from the coil before switching the gun off.

Russell

MarkT:
No, you have to gradually withdraw the screwdriver from an AC electromagnet. A strong magnet will
just make the screwdriver strongly magnetized.

So how you explain this thing?


russellz:
Better still add a coil of substantial wire like this:

+1 for that - it's a ripper!

Did you make that coil (on a wooden mandrel)? Presumably.

I think the magnetizer is just magnets but what about the demagnetizer????? :slight_smile:

Paul__B:
Did you make that coil (on a wooden mandrel)? Presumably.

Yes, originally made to demagnetise the jaws of my lathe chuck to stop it attracting cast iron dust.

Russell.

aisc:
it is of course also a no-no for electronics.

Why is that then? Magnetic fields do not have a detrimental effect on electronic components.

MarkT:
No, you have to gradually withdraw the screwdriver from an AC electromagnet. A strong magnet will
just make the screwdriver strongly magnetized. The gradual movement to weaker and weaker AC field
allows the magnetization to spiral around the hysteresis curve inwards towards the origin.

We used to do exactly the same thing with battle ships when I worked for the Admiralty. Same thing but a slightly different scale.

I've repaired electronics for over 20 years. I've always kept my screwdriver tips magnetized. No problems.

I even did some experiments touching the tips to a floppy disk. It was not enough to damage them.

Short YouTube video about magnetize and demagnetize a screwdriver.

SagarDev:
I think the magnetizer is just magnets but what about the demagnetizer????? :slight_smile:

They do not work well.

Supposedly you rub the screwdriver back and forth going up a step at a time.

Ac is the only effective way.

Grumpy_Mike:
Why is that then? Magnetic fields do not have a detrimental effect on electronic components.
We used to do exactly the same thing with battle ships when I worked for the Admiralty. Same thing but a slightly different scale.

I was always under the impression (hand-me-down knowledge) magnetism and static were to be avoided when working with electronics and in particular with data.

FWIW I uploaded a sketch to my ATTiny a couple of days ago. I popped it out of the programming board I made and into a newly built sensor. Try as I might I could not get the new sensor to transmit. I did everything except rebuild the sensor and it still did not work. Finally I resorted to uploading the sketch again. It turns out the new sensor was working, the problem was my sketch had somehow become corrupted in the ATTiny. I wasted a whole day trouble shooting this problem which turned out not to be a hardware issue.

In trying to determine the cause of the corruption, I recall having used my small (now magnetized) screwdriver while working with the sensor. Not certain if the screwdriver was the cause, but it is my prime/only suspect.

My original post follows this recent experience.

So am I on the wrong track and can I safely poke around with my magnetized screwdriver without fear of corrupting anything?

I was always under the impression (hand-me-down knowledge) magnetism and static were to be avoided when working with electronics and in particular with data.

Static yes, magnets no.
The only thing a magnet could interfere with is the magnetic storage on a disc, and a screwdriver is not likely to be strongly enough magnetised that it could interfere with the disc in your computer.

Not certain if the screwdriver was the cause, but it is my prime/only suspect.

The screwdriver had been framed.

So am I on the wrong track and can I safely poke around with my magnetized screwdriver without fear of corrupting anything?

Yes, your screwdriver caused no harm.

@Grumpy_Mike: Lol and thanks for setting me straight. I guess I owe my screwdriver an apology and will probably let it retain its magnetized state.

Boardburner2:
Supposedly you rub the screwdriver back and forth going up a step at a time.

Ah! That would explain it!

You generate your own "AC". :grinning:

Grumpy_Mike:
Static yes, magnets no.
The only thing a magnet could interfere with is the magnetic storage on a disc, and a screwdriver is not likely to be strongly enough magnetised that it could interfere with the disc in your computer.

Inside a hard drive is a lineair motor for the heads, with two very strong neodymium magnets very close to the spinning platters.
Leo..

Grumpy_Mike:
The only thing a magnet could interfere with is the magnetic storage on a disc,...

Ferrites, too (IF components, radio stuff.)
(And CRTs. A long time ago I brought some samarium-cobalt magnets home from work and observed their effects on the "picture tube". Naively I believed that the TV's own degaussing coil would fix it. It didn't. Reading up on that, the text said that it would only work once the TV was cold. I kept it off several days and still those patterns remained. Fortunately, Radio Shack still sold a considerable degaussing coil (the one in the set is for trivial magnetization) that worked great.)

Could be that the degaussing PTC was shot. I have replaced bucketloads of them.
You could hear if the degaussing circuit was still ok by the short growl the TV made from a cold start.
I usually took several cold starts to remove the coloured blobs.
A degaussing wand fixed it instantly.
Leo..