Re: Drilling through a magnet?
 

Better to know what is bad than nothing at all. :D

I did indeed ask my physics teacher today what would happen if you guys do indeed get the hole cut. I would tell you what she said but I'll let you figure out for yourselves. Everything is more fun that way. :D

Re: Drilling through a magnet?
 

Regarding the plasma cutter: Sounds expensive. We don't have one. :P

Once our mill gets set up and such, I'll ask our mentor if he thinks it will be okay to cut through the magnet.

Thanks for the help!

Re: Drilling through a magnet?
 

Hey! I'm still not 50 years old! ;)
...and about drilling, too!

Re: Drilling through a magnet?
 

FYI, it's not a great idea to try and machine or grind Neodymium-Iron-Boron magnets, as the resulting dust is flammable and toxic gas is produced if it does catch fire.

Re: Drilling through a magnet?
 

Ed,
If I had to make a defintion of "old" then it would at least be anything manufactured before I was born. I could concede anything with hollow state devices, so that could get you into the sixties for some items and maybe include Don at the same time. I have had the chance to work on some antiques in my time. Some were fun to restore, others were a tribute to the bad radio/TV shop techs of the early fifties. I hate coming behind someone else and trying to fix their attempts at repairs. Don will like this one. I had a friend who inherited a Heathkit from a deceased friend. It was a "Cheyenne" transmitter that the owner was modifying into some kind of exciter. There was a mod article in 73 I think way back when. My friend wanted me to return it to working order as a simple transmitter. It did AM or CW and was screen modulated. Things were so convoluted that I had to rip it all out and start over. Luckily I had the original manual. It was a multimonth project but I did get it working. When you run transceivers all the time it is hard to remember what the "spot" switch is and how to use it. The kit came out in the days before injection molded plastic knobs. All the knobs were aluminum and when you had a little RF on the chassis, you knew about it immediately. I don't think my friend ever put it on the air.

Re: Drilling through a magnet?
 

Maybe somebody should try the services of an EDM shop.
"Electric Discharge Machining": intense, sharp, repeated sparks (from a custom electrode shaped like the desired hole) erode the hard material, immersed in liquid bath to flush the debris out of the gap and keep the piece and tool cool. As the sparks jump the 3-mil gap and erode the floor of the erosion pit, the tool moves slowly downwards.
The tools tend to be graphite, copper. or tungsten-copper so they erode much slower than the workpiece (probably because they have high thermal conductivity, good toughness, high melting temp, or other things. The piece needs to be conductive. So Neodymium, Samarium, or Alnico would work fine,
but ceramic (aka ferrite) might not be applicable.
Not sure the price, maybe $50-$100, probably too much, but it would probably work OK, and not much does for machining magnets.
Almost all good materials for permanent magnets tend to be especially hard and brittle. There is a reason. The same high density of crystal defects and grain boundaries that keeps magnetic domains from migrating and allowing the locked-in field to relax, also prevent soft deformation of grains and mechanical yielding. It's not quite a law of physics, but is like a rule of basic materials.
Maybe water-jet cutting could work, but it would be slower than most materials. Maybe there should be an acid-jet cutting - most magnetic metals are pretty rustable... an amateur could try putting one drop of CLR or pool acid (hydrochloric acid) in the middle of a magnet disc every so often, then rinsing it, drying it, and putting a drop only in the dimple it made, for some days in a row. Maybe color the top face with a black marker everywhere but the middle, to keep acid wetness from spreading sideways too much.
Just a lot of perspective I thought I could share...