scrounged parts

[GreenTeam]

I am scrounging alot of my parts for generator builds as a proof of concept before I get the green light
to move on to the big toys! So basically, I am building a little 6 coil axial flux in what I call test bench configuration
( barely half finished ). And my magnets I am using are salvaged from hard drives.  I estimate that they are at least N42
and some much much higher!. My magnet rotor is going to be a metal disc I bought at home hardware and its something to do
with electrical light boxes or junction boxes., But, I found four of them and they are exactly like 12 CM across or so. They are flat, round, clean
and cheap!! My solders I found in the bottom of a tool box lol.
But back to the magnets, can I cut a hard drive magnet in half? Or will it turn into a smaller N S magnet? I read that they are basically two magnets stuck together in the middle. Is this so?

[SparWeb]

The simple answer is yes, you can cut magnets.  Not it's not easy.  Get the finest hacksaw blade you can find, and get lots of them.

IIRC, they are polarized through the thickness, and usually one end is N and the other end is S, as you say.  If you cut the crescent in half you usually end up with two good magnets.

Here's a thread from a long time ago:  https://www.fieldlines.com/index.php/topic,147665.msg1022200.html#msg1022200

That member went pretty wild.  It was fun to see.

[SparWeb]

Here's how it looked with HD magnets cut in half.
Flip one half over, and then both faces are NN.
That guy salvaged a LOT OF HARD DRIVES.

[ Specified attachment is not available ]

[GreenTeam]

Yes, so far I salvaged at least 20 or more hard drives. And bought 40 more off of Craigslist. Does anyone know a simple way of rating what N level they are?

[electrondady1]

 go to a pawn shop and pick up a used tile saw.  the diamond blade cuts both ceramic and neo magnets easily. you will find the magnets to be of different thicknesses . i spent lots of time adding thin mags to thick mags in order to come up with a uniformly  thick  magnet stack.  used skill saw/table saw blades can be had for cheap and make suitable backing rotors.

[GreenTeam]

Yes I found that out also ! I think I am going to be stacking hard drive magnets up also and maybe cementing them. I think thst my surface mqgnet will be the thickest and strongest one though. So far I estimate some of them to be N42, and some much much higher.

[hiker]

Lowe’s or Home Depot,,Have small Neo mags,,been awhile sense I’ve bought any ,,believe they go for around 4 bucks for a stack of  Three,,built a few sawblade mills ,,mainly I used ceramic mags topped with a couple neo’s  for extra strength,,used super glue ,,then surrounded with Epoxy Putty,,it’s a hard as rock epoxy ,,that’ stands up to vibrations and heat,,Lowe’s or Home Depot,,good luck with your Build,,😜

[SparWeb]

Getting all the magnets to match perfectly isn't necessary.  They will all be close enough.  I don't know for sure, but I bet there isn't much variation in HD internal components, at the metallurgical/material level, except for the platens.

[mbouwer]

In their answers in the topic Active Pitchcontrol on page 36 

in Reply # 886 and in Reply # 888

Bruce S and Electrondady1 give good responses on the stacking of magnets.

https://www.fieldlines.com/index.php/topic,145925.875.html

[MagnetJuice]

Stacking magnets that high is a waste of magnetic flux.

If there is a need for stacking, it should be done to produce a magnet that is not deeper than a cube. Adding more magnets is wasteful because the last magnets are too far from the stator coils to add any significant flux to produce voltage.

Can ceramic magnets be combined with neodymium magnets?

Yes, but there is no benefit of doing that because the neo magnet is so strong that it removes the magnetism of the weaker ceramic magnet.

I have conducted experiments and in all cases, the strong neodymium magnet leaves the ceramic magnet with no magnetization on one side and a very weak pole on the other side.

Stacking neodymium magnets of different magnetic strength will have the same effect. The stronger magnets realign the magnetic domains of the weaker magnets. However, the difference in magnetic strength between an N35 and a powerful N52 is not as much as the difference between a neo and a ceramic.

Therefore, it is ok to combine neodymium magnets of different magnetic strengths. There will be some loses, but they are not significant.

Ed