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removing ceramic magnets
By blueyonder, Section Newbies Posted on Sat Sep 29th, 2007 at 09:54:10 PM MST
are thay toxic

never before have i played about with magnets.
so now i have a rotor 4 1/8" dia and would like to shave off about five mm.
on the rotor are ceramic magnets four .90deg each.
is it possible i can turn the rotor in a lathe and just treat it like a bit metal.
as yet i am only thinking. i do understand there verry brittle. like a floor tile.
as far as i know floor tiles are cut wet with a diamond disc.
the ceramic is about 8mm thick . i want to leave about 3mm or 4mm.
then put neo on top .the same pole setup. will bond them on.
i could grind them with a stone cutting disc.
but that makes a lot of dust.
dos ceramic obsorb water.
theres a few chips broken off allready.
so are thay toxic or am i just thinking negitive.
so how best to reduse the dia on rotor.
be nice to hear from others who cut magnets

removing ceramic magnets | 9 comments (9 topical, 0 editorial)

Re: removing ceramic magnets (3.00 / 0) (#1)
by etownlax on Sat Sep 29th, 2007 at 08:11:37 PM MST
(User Info)

I have no idea if they are toxic... But I'd assume that ANY DUST of ANYTHING can't be good for your lungs. Miners used to get blacklung from the coal dust.

However... Just don't forget that you have Magnets Spinging around fairly fast. If a piece of steel were to get caught in the magnets grip it would fly onto the spinning disk and then be thrown very fast. Be careful

Re: removing ceramic magnets (3.00 / 0) (#2)
by Flux on Sun Sep 30th, 2007 at 12:58:11 AM MST
(User Info)

The main trouble you will have is the extreme brittleness and this combined with the tendency to shatter bits off with the heat of machining will make things difficult.

With extreme care you may be able to turn them with a diamond tool with a large jet of water cooling them and very light cuts. Tungsten carbide will probably not touch them. They cut with a diamond saw and a large jet of water fairly easily.

The waste material is not problematic like SmCo or neo but clings everywhere and obscures what you are doing.

Flux

[ Parent ]

Re: removing ceramic magnets (3.00 / 0) (#3)
by electrondady1 on Sun Sep 30th, 2007 at 06:26:47 AM MST
(User Info)

check to see how the mags are bonded to your rotor(adhesive)
i had good luck harvesting speaker magnets by just heating them up in a toaster oven to about 300F.
wear gloves!

[ Parent ]

Re: removing ceramic magnets (3.00 / 0) (#4)
by wpowokal on Sun Sep 30th, 2007 at 07:20:16 AM MST
(User Info)

Since you have or have access to a lathe why not machine a new rotor for your magnets, seems a more elequent answer to me.

allan down under
A life lived in fear is a life half lived.

Re: removing ceramic magnets (3.00 / 0) (#5)
by hiker (hiker.wild[at]yahoo[dot]com) on Sun Sep 30th, 2007 at 10:57:39 PM MST
(User Info)

any chance of knocking the ceramics off and just using neoes??
i have used a bench grinder[holding mags in hand] in the past with ceramic mags--takes awhile.what really surprized me was the mags barely got warm...
must be why they use ceramic tiles on the space shuttle..
ps: wear a dust mask if your going to grind them...
WILD IN ALASKA
[ Parent ]

Re: removing ceramic magnets (3.00 / 0) (#6)
by Capt Slog (Capt.Slog(at this)gmail.com) on Mon Oct 1st, 2007 at 07:47:05 AM MST
(User Info)

I've cut them.

I used a water cooled/lubricated diamond dick that was about 2.5mm thick, but I only cut some small magnets which were 50mm x 25mm x 5 mm into little blocks. The ones I did cut very easily, and I had no problems at all. I broke a couple of pieces because they were hand held and I moved slightly.

How you would cut the amount you want off a disk like that though is beyond me. As others have said, it isn't worth the effort, knock them off and start again.
"Slowly changing the world, one watt at a time!"

Re: removing ceramic magnets (3.00 / 0) (#7)
by vawtman (vawtman(at)charter(dot)net) on Tue Oct 2nd, 2007 at 04:50:43 PM MST
(User Info)

Hi Blueyonder
So your trying to boost the power output of a dc motor by adding neos.Interesting

Has anyone tried this?

Ceramic mags can take pretty much take all the heat you can throw at them and still hold their magnetism(unlike neo)but become very brittle.

Have fun and nice blades.

Re: removing ceramic magnets (3.00 / 0) (#8)
by TomW on Tue Oct 2nd, 2007 at 05:33:38 PM MST
(User Info)

Vman;

So your trying to boost the power output of a dc motor by adding neos.Interesting

Has anyone tried this?

Yeah, did that long ago with a TDM it was a waste of time. No increase in output but noticeable drag increase. I did a diary on it with numbers if you can hunt it down

Cheers.

TomW

"Education consists mainly of what we have unlearned."--Mark Twain
[ Parent ]

Re: removing ceramic magnets (3.00 / 0) (#9)
by blueyonder (windwoodgood at yahoo dot co dot uk) on Tue Oct 2nd, 2007 at 06:34:05 PM MST
(User Info)

not sure but i am replying as in a comment.
so thanks for all the advice. as it happend it was all good advice.
so i did it myway. no 1. put rotor in lathe and started to turn down with lathe tool bit. it was looking ok. but seamed to be taking a long time.
bits were comming off and bits of magnet sticking every whare.
so check lathe tool . it looked blunt so put new tool in and try again.#
sparks etc. looked like it was working .
but on checking tool it was blunt aswell.
ok try no 2. new diamond disc cutter in small hand held grinder.
this looked much better lots of dull orange sparks now. so it was working ok.
rotor was getting a wee bit smaller.
soon the diamond cutter was blunt. it was only a cheap one ment for cutting bathroom tiles or kitchen tiles.
on checking the size it was only one 1/8" smaller.(the rotor)
so now i think i will try stone cutting discs on small angle grinder.
new 4-1/2" disc. now i have water on it but going every whare a face mask .
a breathing mask and big thick gloves..
but soon the stone cutting disc was worn right down.
ok put new disc on and try again. it was working but not great.
on checking the rotor it was still to big. oh.
it was also not a levbal finish all chewed up.
so after much fresh air in the outside .
i returned and got the 9" hand held grinder with nice new 9" cutter..
much better. but so much dust every whare.
so rotor was in the lathe and turning while i set grinder to go other way .
a very messy job . i put big sheet of metal behind lathe and that most of the magnetic dust stuck on it .
so now rotor was the correct size.
ok now i am trying the neos on it . i had two north two south poles.
still got ceramic magnets on rotor.
now i put the new mags on.
so what i have are 25mm x 10mm x 3mm n42.
after a long time messing about i have sevan mags on each pole.
28 mags in all. the neos were stuck to the ceramics.
now for a trial fit. i still had a good air gap so was able to put insulating tape all round in case neo got stck on stater.
was verry happy. so now put rotor inside stater.
sumthing was wrong as it was jammed solid.
looking verry close i could see neos are now stuck to the metal shoes on stator.
tape has streched to allow mags to move.
it was no good rotor and stator were solid.
so my new plan was take all the old ceramic mag of roter.
and i did by hitting it with a hammer.
it was great the ceramic just shatterd.
only took five mins and i had a nice clean rotor.
trying again i put neos back on . tried it but no flux .
rotor was spining free.
try again this time i put two small mags on one on top each other /
but to much flux this time. rotor was turning by hand ok but would never turn in a wind maybe a tornado.
it was interesting but if i can think of how i can get this working i will.
so what have i got in mind . to send off for 24 2"X 1" X.5" MAGS.
but i had to try and do what i done. messy dangerous. lots of time.
but im learning and love messing about.
i wont ever get past the gogging with noes. and if i did would only be the same as before.
i will keep looking on this forum for help and advise.
maybe i would be better to spend my time learing to spell.
so thanks all . you were right flux .
its a ill wind that dos no good

removing ceramic magnets | 9 comments (9 topical, 0 editorial)

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