Geoff ive been assured by the machine shop that it is not brittle and will not shatter. The alloy is Stellite which is going to be welded to the mild steel teeth so it is fused together. Stellite is a alloy containing cobalt, chromium, and tungsten, usually used for high-speed, heavy-duty, high temperature cutting tools im assured that it is shock resistant unlike Tungsten Carbide and safe to be used on the bot.

Chris - http://www.featherweights.org/forum