Use 7/64 as tap drill and 9/64 as clearance drill
Taps and dies are used in threading. To make an internal thread, you drill a hole smaller than the thread width, then slowly screw a 'tap' into it cutting a thread very slowly. -For an external thread, you choose a rod or bolt larger than the final thread, then screw a hard, threaded disc down onto it.
acquire correct tap from hardware or automotive supplier. Drill smaller hole through EGR port boss on head. Drill larger hole , size stated on tap to same depth as on intake port. then tap. If metric thread tap cannot be acquired a tapered pipe thread tap will also work. Threads are very close and will seal because of taper.
You drill the bolt out that is snapped off in the engine,with drill bit made to drill through metal. Then use a thread maker,tap. Auto parts stores carry these. I no u can get at autozone. The tap makes new threads.
Drill and tap it for what?
Your meaning is not clear . -If you are going to tap an M5 thread, then use a 5/32 drill bit. If you want a hole that an M5 bolt will fit through, use a 7/32drill bit.
I would use an 18mm or 23/32 drill bit, in general, although it does partly depend on the thread type ( UNF, UNC etc) and the material .
I use a 3/8 bit for tapping fine thread, or a 11/32 for coarse threads.
Your meaning is not clear. - If you are going to tap the threads in, use a 7/32 drill bit. If you want a hole that this bolt will slip through, use a 9/32 drill bit.
For a cut tap the correct drill size is a #17 drill, which has a diameter of .173 inches.
The recommended drill size for tapping threads with an M3 tap is 2.5mm.
For a half-inch tap (specifically a 1/2"-13 tap, which is common for coarse threads), the recommended drill bit size is typically 27/64 inches, or approximately 10.7 mm. This size provides the appropriate clearance for the tap to create threads in the material. Always consult a tap drill chart for specific applications, as fine thread taps may require different sizes.