
| recomm tap li | ended mits 1 | internal thread pitch diameter limits | |||
| thread size/pitch | class 2B | class 3B | min all classes (Basic) | max class 2B | max class 3B |
| 3/4 - 16 | H5 | H4 | 0.7094 | 0.7159 | 0.7143 |
| 7/8 - 9 | H6 | H4 | 0.8028 | 0.8110 | 0.8089 |
| 7/8 - 14 | H6 | H4 | 0.8286 | 0.8356 | 0.8339 |
| 1” - 8 | H6 | H5 | 0.9188 | 0.9276 | 0.9254 |
| 1” - 12 | H6 | H4 | 0.9459 | 0.9535 | 0.9516 |
| 1-1/8 - 7 | H8 | H6 | 1.0322 | 1.0416 | 1.0393 |
| 1-1/8 - 8 | H8 | H6 | 1.0438 | 1.0528 | 1.0505 |
| 1-1/8 - 12 | H6 | H5 | 1.0709 | 1.0787 | 1.0768 |
| 1-1/4 - 7 | H8 | H6 | 1.1572 | 1.1668 | 1.1644 |
| 1-1/4 - 8 | H8 | H6 | 1.1688 | 1.1780 | 1.1757 |
| 1-1/4 - 12 | H6 | H5 | 1.1959 | 1.2039 | 1.2019 |
| 1-3/8 - 6 | H8 | H6 | 1.2667 | 1.2771 | 1.2745 |
| 1-3/8 - 8 | H8 | H6 | 1.2938 | 1.3031 | 1.3008 |
| 1-3/8 - 12 | H6 | H5 | 1.3209 | 1.3291 | 1.3270 |
| 1-1/2 - 6 | H8 | H6 | 1.3917 | 1.4022 | 1.3996 |
| 1-1/2 - 8 | H8 | H6 | 1.4188 | 1.4283 | 1.4259 |
| 1-1/2 - 12 | H6 | H5 | 1.4459 | 1.4542 | 1.4522 |
| 1-3/4 - 5 | H8 | H7 | 1.6201 | 1.6317 | 1.6288 |
| 2 - 4 1/2 | H8 | H7 | 1.8557 | 1.8681 | 1.8650 |
1Tap H limit selected for 3B will also produce thread to 2B.
| thread | size | recommended tap | internal thread produ | ct limits — class 6H | ||
| nominal diameter (mm) | pitch (mm) | limit number | pitch d (m min | iameter m) max | pitch d (i min | iameter n) max |
| 1,6 2 2,5 | 0,35 0,4 0,45 | D3 D3 D3 | 1,373 1,740 2,208 | 1,458 1,830 2,303 | .05406 .06850 .08693 | .05740 .07205 .09067 |
| 3 3,5 4 | 0,5 0,6 0,7 | D3 D4 D4 | 2,675 3,110 3,545 | 2,775 3,222 3,663 | .10531 .12244 .13957 | .10925 .12685 .14421 |
| 4,5 5 6 | 0,75 0,8 1 | D4 D4 D5 | 4,013 4,480 5,350 | 4,131 4,605 5,500 | .15789 .17638 .21063 | .16264 .18130 .21654 |
| 7 | 1 | D5 | 6,350 | 6,500 | .25000 | .25591 |
| 8 | 1,25 | D5 | 7,188 | 7,348 | .28299 | .28929 |
| 10 | 1,5 | D6 | 9,026 | 9,206 | .35535 | .36244 |
| 12 14 16 | 1,75 2 2 | D6 D7 D7 | 10,863 12,701 14,701 | 11,063 12,913 14,913 | .42768 .50004 .57878 | .43555 .50839 .58713 |
| 20 24 30 | 2,5 3 3,5 | D7 D8 D9 | 18,376 22,051 27,727 | 18,600 22,316 28,007 | .72346 .86815 1.09161 | .73228 .87858 1.10264 |
| 36 | 4 | D9 | 33,402 | 33,702 | 1.31504 | 1.32685 |