Tap drill chart
Tap drill sizes for 53 inch threads. The drill listed gives about 75% thread. Click a thread for its full page.
| Thread | Series | Tap drill (75%) | Inches | mm | Thread | 50% drill | Clearance, close | Clearance, free |
|---|---|---|---|---|---|---|---|---|
| #0-80 | UNF | 3/64" | 0.0469 | 1.19 | 81% | #55 | #52 | #50 |
| #1-64 | UNC | #53 | 0.0595 | 1.51 | 67% | 1/16" | #48 | #46 |
| #1-72 | UNF | #53 | 0.0595 | 1.51 | 75% | #52 | #48 | #46 |
| #2-56 | UNC | #50 | 0.0700 | 1.78 | 69% | #49 | #43 | #41 |
| #2-64 | UNF | #50 | 0.0700 | 1.78 | 79% | #48 | #43 | #41 |
| #3-48 | UNC | #47 | 0.0785 | 1.99 | 76% | #44 | #37 | #35 |
| #3-56 | UNF | #45 | 0.0820 | 2.08 | 73% | #43 | #37 | #35 |
| #4-40 | UNC | #43 | 0.0890 | 2.26 | 71% | #41 | #32 | #30 |
| #4-48 | UNF | #42 | 0.0935 | 2.37 | 68% | #40 | #32 | #30 |
| #5-40 | UNC | #38 | 0.1015 | 2.58 | 72% | 7/64" | #30 | #29 |
| #5-44 | UNF | #37 | 0.1040 | 2.64 | 71% | #35 | #30 | #29 |
| #6-32 | UNC | #36 | 0.1065 | 2.71 | 78% | #32 | #27 | #25 |
| #6-40 | UNF | #33 | 0.1130 | 2.87 | 77% | #31 | #27 | #25 |
| #8-32 | UNC | #29 | 0.1360 | 3.45 | 69% | #27 | #18 | #16 |
| #8-36 | UNF | #29 | 0.1360 | 3.45 | 78% | #26 | #18 | #16 |
| #10-24 | UNC | #25 | 0.1495 | 3.80 | 75% | #20 | #9 | #7 |
| #10-32 | UNF | #21 | 0.1590 | 4.04 | 76% | #18 | #9 | #7 |
| #12-24 | UNC | #16 | 0.1770 | 4.50 | 72% | #12 | #2 | #1 |
| #12-28 | UNF | #14 | 0.1820 | 4.62 | 73% | #10 | #2 | #1 |
| #12-32 | UNEF | #13 | 0.1850 | 4.70 | 76% | #9 | #2 | #1 |
| 1/4-20 | UNC | #7 | 0.2010 | 5.11 | 75% | 7/32" | Letter F | Letter H |
| 1/4-28 | UNF | #3 | 0.2130 | 5.41 | 80% | #1 | Letter F | Letter H |
| 1/4-32 | UNEF | 7/32" | 0.2188 | 5.56 | 77% | #1 | Letter F | Letter H |
| 5/16-18 | UNC | Letter F | 0.2570 | 6.53 | 77% | Letter J | Letter P | Letter Q |
| 5/16-24 | UNF | Letter I | 0.2720 | 6.91 | 75% | 9/32" | Letter P | Letter Q |
| 5/16-32 | UNEF | 9/32" | 0.2812 | 7.14 | 77% | Letter L | Letter P | Letter Q |
| 3/8-16 | UNC | 5/16" | 0.3125 | 7.94 | 77% | Letter Q | Letter W | Letter X |
| 3/8-24 | UNF | Letter Q | 0.3320 | 8.43 | 79% | Letter S | Letter W | Letter X |
| 3/8-32 | UNEF | 11/32" | 0.3438 | 8.73 | 77% | Letter T | Letter W | Letter X |
| 7/16-14 | UNC | Letter U | 0.3680 | 9.35 | 75% | 25/64" | 29/64" | 15/32" |
| 7/16-20 | UNF | 25/64" | 0.3906 | 9.92 | 72% | 13/32" | 29/64" | 15/32" |
| 7/16-28 | UNEF | Letter Y | 0.4040 | 10.26 | 72% | Letter Z | 29/64" | 15/32" |
| 1/2-13 | UNC | 27/64" | 0.4219 | 10.72 | 78% | 29/64" | 33/64" | 17/32" |
| 1/2-20 | UNF | 29/64" | 0.4531 | 11.51 | 72% | 15/32" | 33/64" | 17/32" |
| 1/2-28 | UNEF | 15/32" | 0.4688 | 11.91 | 67% | 15/32" | 33/64" | 17/32" |
| 9/16-12 | UNC | 31/64" | 0.4844 | 12.30 | 72% | 33/64" | 37/64" | 19/32" |
| 9/16-18 | UNF | 33/64" | 0.5156 | 13.10 | 65% | 17/32" | 37/64" | 19/32" |
| 5/8-11 | UNC | 17/32" | 0.5312 | 13.49 | 79% | 9/16" | 41/64" | 21/32" |
| 5/8-18 | UNF | 37/64" | 0.5781 | 14.68 | 65% | 19/32" | 41/64" | 21/32" |
| 3/4-10 | UNC | 21/32" | 0.6562 | 16.67 | 72% | 11/16" | 49/64" | 25/32" |
| 3/4-16 | UNF | 11/16" | 0.6875 | 17.46 | 77% | 45/64" | 49/64" | 25/32" |
| 7/8-9 | UNC | 49/64" | 0.7656 | 19.45 | 76% | 51/64" | 57/64" | 29/32" |
| 7/8-14 | UNF | 13/16" | 0.8125 | 20.64 | 67% | 53/64" | 57/64" | 29/32" |
| 1-8 | UNC | 7/8" | 0.8750 | 22.22 | 77% | 59/64" | 1-1/64" | 1-1/32" |
| 1-12 | UNF | 59/64" | 0.9219 | 23.42 | 72% | 61/64" | 1-1/64" | 1-1/32" |
| 1-1/8-7 | UNC | 63/64" | 0.9844 | 25.00 | 76% | - | - | - |
| 1-1/8-12 | UNF | 1-3/64" | 1.0469 | 26.59 | 72% | - | - | - |
| 1-1/4-7 | UNC | 1-7/64" | 1.1094 | 28.18 | 76% | - | - | - |
| 1-1/4-12 | UNF | 1-11/64" | 1.1719 | 29.77 | 72% | - | - | - |
| 1-3/8-6 | UNC | 1-7/32" | 1.2188 | 30.96 | 72% | - | - | - |
| 1-3/8-12 | UNF | 1-19/64" | 1.2969 | 32.94 | 72% | - | - | - |
| 1-1/2-6 | UNC | 1-11/32" | 1.3438 | 34.13 | 72% | - | - | - |
| 1-1/2-12 | UNF | 1-27/64" | 1.4219 | 36.12 | 72% | - | - | - |
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