It looks like Russell has the answer to drilling them!
Have any of you folks who dream about various magnet shapes ever tried an EDM?
It might not be cost effective in most cases....but here's some numbers to play with:
Most machine shops with a wire edm charge between 50-75 bucks an hour.
The beauty about these machines for those unfamiliar is that it uses brass wire and an electrical current to do the cutting....some cut the work submerged under water with a flush and some just simply flush it with water without submerging.....so no overheating is involved in either case
Someone halfway decent at running a wire edm can get about 6 mm of travel a min. on a material thickness of 1 inch thick. The thicker the cut the slower it has to run. Maybe a little bit faster more if a slight bowing is of no concern ( it might have a slight taper or out of squareness) of about .003-005 thousandths over the 1 inch surface. If the operator is really skilled and knows how to tweak the parameters and the current technology of the machine is the latest and greatest...you can proably push it even faster without too many wire breaks.
The beauty about the wire EDM is that you can cut some really intricate shapes with them...often along 5 axis ( x, y, z, u & v)...this might be benefical for those who like those tighter clearances in the standard electrical motor type of setups.
They also have a "Hole Popper" which works off the same technology, it is for punching through material which is already hardened, such as salvaging an expensive part by "burning" out a tap which has been broken off. These machine also use brass for cutting and a water flush. the tube is hollow and rotates like a drill while forcing water through the center of the tube....they can range from about .006 in diameter to 1/4 in in diameter. If setup correctly some of these hole poppers can really hum right along...a one inch thick piece could probably be drilled in about 30-40 seconds if the paramateres are really tweaked... or 3-5 mins if the operator is having a lazy day.
I use to use this type of equipment on a daily basis with a company which has since closed down. ( globalization...offshored to some remote location)
I would love to have my hands on this equpment again and give it a go on some neo magnets and report back in.
Often I would have two of three of theses machines running at once, but also some sat idle when the work load was light...it would have been a perfect opportunity to tinker around with some neo's while one sat idle....groan
