ronn, the method I was taught for drilling spring steel is to use an ordinary carbide-tipped masonry drill bit with plenty of speed, pressure and cutting oil. If you let the cutting point dry up, the brazed joint between the carbide tip and the steel body of the drill bit immediately melts. You'll have to resharpen the carbide tip fairly often - I use an ordinary bench grinding wheel with light pressure, and of course the wheel finishes up blunt for a while. To give you an estimate of how far you can drill before the bit gets blunt, I've drilled a 3 mm hole through a 5/8" spring steel bar without resharpening during the process, but I then had to resharpen for the next hole. I suggest drilling a pilot hole of about 3-5 mm if you are drilling bigger holes than that.
