Will coballt M35 drill bits break?

M35 drill bits are 5% cobalt and this means the bits can be brittle if used incorrectly. The M35 bits must be used at a slow speed and they will work best and last longer if run at slow working speeds with lubricant. The key purpose of adding up the cobalt is to enhance the heat resistance capacity and durability of the bits. The M2 drill bits are not cobalt, and as such can be run at a normal speed on a power drill.