Can Neodymium (Nd-Fe-B) magnets be drilled and machined?
Not easily or safely. Neodymium sintered magnets behave like a ceramic. They have a tendency to crack and chip when drilled. Additionally, the powder produced when machining these magnets is flammable. Lastly, machining causes heat to build up in the magnet which may result in it being demagnetized. Most likely, a drilled or machined Neo magnet will be made unusable by the process due to breakage, cracking or heat damage.
