Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I was amazed and impressed with the materials used on the crank, liner and valves of these engines, 10/10 Microcosm. 
Carbide drills for PC board drilling are available in very small sizes (RS components, Mouser, Rapid etc.) and will make short work of this suprisingly hard material, and a dremel grind stone to take the burr off the inside after.
Kind regards
Ade