While I’ve never personally drilled through a magnet (yet), I did ask some questions on these forums some years ago, which led to some great discussions about magnets & magnetism you may be interested in reading.
http://www.chiefdelphi.com/forums/showthread.php?t=38420&highlight=questions+about+magnets
Let us know how you make out with the drilling!
And above all, stay safe while doing so! ::safety::
That sounds remarkably like our 1718 mechanical team. Did they slip a camera crew in when I wasn’t paying attention? 
If the magnet is shiny like so many in the inexpensive speakers, it is probably Alnico. That’s Aluminum-Nickel-Cobalt-Iron. It’s hard, somewhere around 45-50 on the Rockwell C scale. Some hard objects are machined, but the cutting geometry of a drill bit isn’t suited for it.
The magnet is very hard,and black.
For the age of the radio- We aren’t sure, it was lying in a pile of old stuff. I couldn’t give you any estimation, other than 10+ years? 
And the magnet- I’m at school now (my lunch hour) and have made some progress on the magnet. I used a 1/2 bit again, and have managed to make a small indentation. I didn’t want to go to much, because the magnet was getting hot (still has it magnetism though!) so I am letting it cool down.
Thanks guys!
A word of caution: use cooling oil or cutting fluid, if you aren’t already. You’re heating and cooling the metal; this can harden it further, making it more difficult to cut. I’ve seen even a heat-treated sprocket take a lot of time and cutting fluid to drill a hole in it. 3 holes were needed in that one, too, and it’s softer than that magnet likely is.
Take your time, use lots of cutting fluid (or cooling oil), and if you aren’t sure you can keep going, stop.
And think of how much extra you’re learning about magnets…
Thanks for the advice!
Apparently, the mill we are getting (On Monday!!!) will have some special bits (I think diamond tipped) so I am going to wait and use that instead.
Never used a mill before, but one of our mentors has, so I will learn to use a mill WHILE brutally learning about magnets! Haha.
*A Blueprint for a Quantum Propulsion Machine
Push on the electromagnetic fields in the quantum vacuum and you should get an equal and opposite force. *
A Blueprint for a Quantum Propulsion Machine
Push on the electromagnetic fields in the quantum vacuum and you should get an equal and opposite force.
That looks really cool. I like the question at the end:
The question is: who has the balls to try it?
The milling cutters you get with your mill may be quite expensive. Someone may get upset if you ruin one trying to bull on through a hard magnet just to see what happens.
I wouldn’t worry so much about the color, as the magnet might not have been ground after sintering. Looks like many of the Samarium Cobalt magnets are black, and still extremely hard.
Grinding or machining anything containing Iron with a diamond isn’t a great idea. Iron has a strong affinity for carbon, which it will gather from the diamond. Grinding steel on a diamond wheel is a good way to ruin it.
I just want to add a point about possibly using a plasma cutter. If you get the magnet too hot it will start to lose its magnetism. Think of it as being lots of miniature magnets all facing one direction, but when you heat it up, the particles shift and they won’t all be facing the same direction. They will be slightly off parallel and the overall field will be weaker.
I know this doesn’t help with cutting. I have no experience with hardness and such, I can just tell you heat is bad for a magnet.
Better to know what is bad than nothing at all.
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.
Regarding the plasma cutter: Sounds expensive. We don’t have one. 
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!
Hey! I’m still not 50 years old! 
…and about drilling, too!
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.
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.
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…