my brother is a tool and die maker, and has some experience working TI heavy feeds and speeds are called for and he recommends never pausing or retracting a drill or mill until cut is finished, because the part will work harden as soon as the pressure is off.
a couple of other notes: One of the first uses of Ti in aircraft was the SR-71(habu) black bird and the learning curve was steep. Part failures were high until they discovered that the chlorine in the water was reacting with the Ti and causing stress cracks. Also trace amounts of chrome from chrome plated tools would cause TI bolts to fail. Part failure at Mach-3+ can be a real E-Ticket ride.
