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Using magnets

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Paul M04/04/2019 09:19:15
18 forum posts

I recently pulled apart a PC hard drive (not solid state) and discovered two very strong magnets.

I have used them frequently for holding ferrous parts together when marking out and spotting for drilling. They are small flat and very useful.

Not something I would have thought of using in the past, but worth retrieving if you have a dead hard drive.

steamdave04/04/2019 09:34:07
406 forum posts
34 photos

Also, the ball bearings are top quality.

Dave
The Emerald Isle

Ian S C04/04/2019 10:48:58
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7300 forum posts
228 photos

Also the ballraces in VHS recorders/players, including some with as small as 3 mm bore in the nylon tape guide rollers, the others are usually 6 mm bore.

Good ferite magnets from old modern speakers, and micro wave ovens.

Ian S C

Edited By Ian S C on 04/04/2019 10:51:15

ega04/04/2019 10:53:01
1133 forum posts
94 photos
Posted by steamdave on 04/04/2019 09:34:07:

Also, the ball bearings are top quality.

Dave
The Emerald Isle

Are they air bearings today?

Ian P04/04/2019 11:38:10
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2078 forum posts
88 photos

Hard disk drive bearings are a whole technology in themself. Lots of different types but I presume development (to reduce cost and increase performance) has slowed as solid state disks become cheaper.

Quite a lot of drives use what I would describe as a plain bearing but its one that can run quietly and continuously at high speed for years with no maintenance. Looks to be done by high precision machining and some sort of hydraulic/dynamic control of a the miniscule amount of lubricant.

HDDs can be a good source of very high quality light duty ballraces but the older the drive is the more likely it will contain parts that are re-usable, modern drives are so highly integrated that the bearings tracks are machined directly into the shafts and housings.

Ian P

V8Eng04/04/2019 13:37:43
1255 forum posts
27 photos

Posted by Paul M on 04/04/2019 09:19:15:

I recently pulled apart a PC hard drive (not solid state) and discovered two very strong magnets.

I have used them frequently for holding ferrous parts together when marking out and spotting for drilling. They are small flat and very useful.

Not something I would have thought of using in the past, but worth retrieving if you have a dead hard drive.

Do not let those magnets get together because separating them needs a lot of force. Don’t ask!

Nicholas Farr04/04/2019 14:16:08
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1807 forum posts
898 photos
Posted by V8Eng on 04/04/2019 13:37:43:

Posted by Paul M on 04/04/2019 09:19:15:

I recently pulled apart a PC hard drive (not solid state) and discovered two very strong magnets.

I have used them frequently for holding ferrous parts together when marking out and spotting for drilling. They are small flat and very useful.

Not something I would have thought of using in the past, but worth retrieving if you have a dead hard drive.

 

Do not let those magnets get together because separating them needs a lot of force. Don’t ask!

Hi, and watch your fingers, as those magnets have quite a sharp snap when they get close to iron or each other.

Regards Nick.

Edited By Nicholas Farr on 04/04/2019 14:16:54

Nigel McBurney 104/04/2019 14:38:39
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556 forum posts
3 photos

Dont get them near to bank cards or other cards as they will wipe the magnetic stripes. I worked for a long time with hard drives,I was working onnce with an actuator engineer who held an actuator up close to his chest to show me some details and promptly wiped out the magnetic stripe on his security pass.

Speedy Builder504/04/2019 14:46:35
1711 forum posts
118 photos

I had some about 4" x 2" x 1" however made the mistake of not using some of the soft iron in the drive as a keeper. Over about 10 years, they lost their strength.

XD 35104/04/2019 14:57:33
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1228 forum posts
83 photos

Here is a useful tool you can make using the magnets you have collected .

**LINK**

Ian P04/04/2019 15:07:52
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2078 forum posts
88 photos
Posted by Speedy Builder5 on 04/04/2019 14:46:35:

I had some about 4" x 2" x 1" however made the mistake of not using some of the soft iron in the drive as a keeper. Over about 10 years, they lost their strength.

Were they rare earth magnets?

When installed in the hard drive they would not have had a keeper so loosing a significant amount of strength in only 10 years is unusual.

Ian P

Robert Atkinson 204/04/2019 17:24:01
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204 forum posts
17 photos

Drives, including older 51/4" ones have other useful parts. The disk platters make good minature surface plates and the spacers between them, tubular paralells or gauge rings (but light alloy not steel) CD-ROM drives also have nice precision ground and polished rods in pairs that the optcal heads run on.

Robert G8RPI.

Robert Atkinson 204/04/2019 17:24:03
avatar
204 forum posts
17 photos

Drives, including older 51/4" ones have other useful parts. The disk platters make good minature surface plates and the spacers between them, tubular paralells or gauge rings (but light alloy not steel) CD-ROM drives also have nice precision ground and polished rods in pairs that the optcal heads run on.

Robert G8RPI.

vintage engineer04/04/2019 19:48:13
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114 forum posts

When I worked in the backrooms of a well know bank, we used to remove the hard drives from all the computers we sold or scrapped and smashed them with a large hammer on a RSJ! I still do it when I scrap a computer.

Ian S C05/04/2019 12:51:05
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7300 forum posts
228 photos

To avoid damage to you or the magnet, and make it easier to get apart, always slide them together, it's easy to trap a little bit of flesh if the magnets have nice square edges.

Ian S C

not done it yet05/04/2019 13:18:03
2808 forum posts
11 photos

Magnets? Look up the ones that go into many home brewed wind turbines. Check out the holding power of one magnet and then consider the pulling force of two discs with perhaps a dozen or more magnets on each disc! The only safe way is to jack the together or apart using threaded rods and nuts, or similar.

XD 35106/04/2019 00:05:47
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1228 forum posts
83 photos

I have a 50sq x 40 mm thick neodymium magnet and i treat that one with respect i can tell you ! I was using it to hold something in place for welding and was returning it to shelf where it lives , as i walked past my steel workbench ) not paying attention as usual ) the hand carrying it got close enough for the magnet to pull my hand into the bench and clamp it there ! It was like i had belted my hand with a lump hammer !

Boiler Bri06/04/2019 03:18:15
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728 forum posts
277 photos

I use small 15mm x3 mm magnets with a 2kg hold to hold things like Allen keys chuck keys and spanners.

Very usefull items.

Bri

mark costello 106/04/2019 18:06:00
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502 forum posts
12 photos

I have about 12" of hard drive magnets, cannot get another within about 6" of it or they get really friendly and will shatter one or two when they meet.

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