RCU Forums - Drilling a cap screw head

Its possble... but very difficult. You need a small precision drill press and a very good quality drill bit. Also a vice to hold the screw ads you drill it.
The reason for the precision equipment is the size ofthe hole possible in a rouchly 4-40 screw's head (I forget the metric size... about 2.5 or 3 mm.) And the hardness of the cap screws used for muffler retension. Any slipping while drillng that small hole, and the drill bit will snap.
If the screw were brass... it would be easier to drill. But a brass screw replacement for the muffler mpuntingscrew wouldn't be strong enough... the threads would shear off.

A member of our club presented me with 2 screws drilled this way for one of my mufflers. He has access to the correct equipment at work.