TappingNPT pipe threads. Thread starter Overland; Start date May 5, 2023; Replies 40 Views 2,484 1; 2; 3; If you drill the correct drill size thru, then maybe start with 10 complete turns of the tap handle to start. I've always left 8 threads on non-gaged stuff. Leaves a little room for a touch-up later if it's ever needed.
MetricISO Fine Tapping Drill Sizes, Metric ISO Coarse Tapping Drill Sizes, UNC UNC, UNF UNS, BSW Whitworth, BSF, BSTP Taper Pipe., BSPF Parallel Pipe, and NPT Taper Pipe. Toggle navigation. Why Choose Us? Products . All Products Threads per Inch Tapping Drill Sizes; Preferred Alternative; mm Inch mm Inch; No 2: 56: 1.85: 1.8: No 3: . 810 658 815 471 904 860 394 125