"Bob La Londe" wrote in message news
"Jim Wilkins" wrote in message news

"David Billington" wrote in message
news
On 18/10/17 22:05, Bob La Londe wrote:
Hi guys. I need to machine away the corner of a neodymium magnet that
needs to go into a hole in a mold. One of the passages for a core
intersects the hole the magnet is going to get pressed into. There really
isn't any other place to put the magnet, and the core is a necessary part
of the casting.

Any tips or suggestions?

The best thing I can think of is to just use the little bench top belt
grinder.

The problem is if the prototype is satisfactory I may find myself making
a bunch of these molds. Hand grinding one is no big deal. 20 or a
hundred... well that could be pretty time consuming.

I know they are fragile. That's why I think grinding is the best option
for just one. I do not want to put a grinding wheel on one of my mills,
and the little no-name mill drill still comes in handy from time to time
(I used it today), so I'm not crazy about filling it up with grit either.




What I've read about those magnets is that they aren't recommended for
machining as the dust is easy to ignite. Also if using to hold a core in a
mould IIRC the magnetic properties are lost at low temperature of less
than 100C so you may be better off looking for another solution.


https://www.kjmagnetics.com/neomaginfo.asp
"Machining the magnets will generate heat, which if not carefully
controlled, can demagnetize the magnet or even ignite the material
which is toxic when burned."


*********

Well since it looks like ordering a shorter length magnet to go in the hole
is a better option I looked and found that KJ magnetics has rare mags rated
for high temperature use. Now to see if there is somebody who can get them
here in a day or so for less than $74 shipping.

*********

McMaster to the rescue. LOL. They were typically outrageously more
expensive, but they had some much higher temperature neodymium mags that
will work ok, and I needed to order some fill in drill bits, teflon rod, and
a couple other things from them anyway.