TAP DRILL SIZE CHART FOR NPT THREADS
(National Pipe Threads)
(National Pipe Threads)
| 1/16 - 27 | "C" | (0.242) |
| 1/8 - 27 | "Q" | (0.332) |
| 1/4 - 18 | 7/16 | (0.438) |
| 3/8 - 18 | 9/16 | (0.562) |
| 1/2 - 14 | 45/64 | (0.703) |
| 3/4 - 14 | 29/32 | (0.906) |
| 1.0 - 11•1/2 | 1•9/64 | (1.141) |
| 1•1/4 - 11•1/2 | 1•31/64 | (1.484) |
| 1•1/2 - 11•1/2 | 1•23/32 | (1.719) |
| 2.0 - 11•1/2 | 2•3/16 | (2.188) |
| 2•1/2 - 8 | 2•39/64 | (2.609) |
| 3.0 - 8 | 3•15/64 | (3.234) |
