If you can manage not to burn the metal while grinding it, you can take advantage of the manufacturer's superior heat treatment and avoid the perils of attempting the same at home.
A couple tips, based on my own experience:
A. Keep the work wet. If there is liquid water on the workpiece, it's not overheated. When in doubt, quench.
B. If the metal is hot enough to burn your fingers, it's too hot. Add water. And pain is an efficient teacher
C. The thinner the area you're working on, the more careful you want to be... there is less thermal mass to suck up the heat and buggering the temper in thin spots is a recipe for premature failure.
D. When using an abrasive wheel/emery wheel for rough-cutting, placing a few layers of wet rags underneath the work will pretty much avoid overheating. Sandwiching the work between two pieces of (sacrificial) aluminum, if it doesn't clog up your cutter, is also a good trick when grinding.
E. Use gentle pressure and let the tool do the work.
F. Perform final shaping with emery cloth or sanding bits. They cut more slowly (and so are easier to control) and reduce heating.
G. Finally, make sure that the abrasives and cutting bits you're using are designed for use on hardened ferrous metals. IIRC, you're looking for tungsten carbide instead of aluminum carbide... but read the packaging to be sure.
Be safe and have fun. And remember: sharp bits of metal + eyeball = pain and possible blindness.
