Machining Strange materials

This topic has 8 replies, 7 voices, and was last updated 3 April 2011 at 12:57 by Richard Parsons.

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1 April 2011 at 18:00 #66381
Richard Parsons
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@richardparsons61721
I am considering making the ‘Eureka’ by Artificer (published M.E. Feb 1949) as my late summer project –If (and in Hungary it is a big If) I can get all the materials-.

I think that there is a problem with artificer’s design. This is the Coil which is wound within the ‘balance wheel’. This could cause both static and dynamic imbalances. To overcome this I am thinking of replacing it by a permanent magnet.

I have never machined un-magnetised Samarium magnets and ferrite bars. Can anyone give me help on how to do it?
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1 April 2011 at 18:00 #5467
Richard Parsons
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@richardparsons61721
1 April 2011 at 23:19 #66391
John Olsen
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@johnolsen79199
I don’t know about samarium cobalt, but I beleive the ferrite is best cut with a diamond saw. I haven’t done this myself, but there was a book published locally on building an alternator for alternative energy use, and that is how he cut the ferrite magnets he used.

regards

John
2 April 2011 at 09:07 #66398
Clive Hartland
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@clivehartland94829
I would think a Diamond saw would be the only thing that would cut it.

The other problem may be holding it as pressure can crack it.

I had to grind a component that had two glass prisms attached, the problem was heat, I cooled it with a drip of suds and went very carefully as each item cost in excess of £500.

Clive
2 April 2011 at 09:55 #66401
Gordon W
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@gordonw
Like the above people I’ve never tried cutting samerium magnets, never heard of it before. Have tried turning ferrite rod with brazed carbide tip, did about 10 mm before the tip was scrap, and the finish was awful. Cut ok with a thin disc in angle grinder. I do know there are many different mixes ,but have no idea whats what.
3 April 2011 at 03:17 #66427
Sam Stones
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@samstones42903
Hi Richard,

Please have a look at the thread titled Graphite Bushes. Go down to my posting date/time 19/07/2010 06:42:51

I mention the problem I had with glass-bead filled plastic material, when beads found their way under and jammed the ML7 saddle.

I can imagine the problems if the material was in any way magnetic.

Good luck,

Sam
3 April 2011 at 11:16 #66436
MICHAEL WILLIAMS
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@michaelwilliams41215
Beware that ‘permanent’ magnets which are not in a proper magnetic circuit will lose their strength over time . This variation may cause much larger errors than the possible imbalance of a coil .

Hard magnetic materials are usually cut in industry using a high speed elastic grinding wheel .
3 April 2011 at 11:43 #66438
Anonymous
Hmmmm, according to Wikepedia dry samarium cobalt powder has a low ignition temperature. If it does catch fire it will be very difficult to control; presumably like most metal fires.

In essence both these materials are very hard (mechanically) but also very brittle. As has been stated they can only be machined by grinding. Samarium cobalt is also hard magnetically, while ferrite is usually soft magnetically.

Regards,

Andrew
3 April 2011 at 12:57 #66443
Richard Parsons
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@richardparsons61721
I would like to thank everyone for their help. It is always a good idea to ask those who know about such things and have been there, done it and got the ‘Tee’ shirt, first.

Andrew I became aware of that point. Cobalt is similar to Nickel. Which in has an alloy (with aluminium) called ‘Raney Nickel’. It is very pyrophoric.

The problem with Eureka is that is that it is not a true Hipp movement. The impulse is given irrespective of the degree of oscillation of the balance wheel.

‘Hum Ho’ ‘That ‘cat won’t jump’ so back to the bakky-pipe and the drawing board!

Once again thanks to everyone who has helped.

Regards

Dick
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