| Thread Size | Basic Major Dia. | Tap Drill Size |
|---|---|---|
| #0-80 | .0600 | 3/64 |
| #2-56 | .0860 | #50 |
| #2-64 | .0860 | #50 |
| #4-40 | .1120 | #43 |
| #4-48 | .1120 | #42 |
| #5-40 | 1250 | #38 |
| #5-44 | .1250 | #37 |
| #6-32 | .1380 | #36 |
| #6-40 | .1380 | #33 |
| #8-32 | .1640 | #29 |
| #8-36 | .1640 | #29 |
| #10-24 | .1900 | #25 |
| 10-32 | .1900 | #21 |
| 1/4-20 | .2500 | #7 |
| 1/4-28 | .2500 | #3 |
| 5/16-18 | .3125 | F |
| 5/16-24 | .3125 | I |
| 3/8-16 | .3750 | 5/16 |
| 3/8-24 | .3750 | Q |
| 7/16-14 | .4375 | U |
| 7/16-20 | .4375 | 25/64 |
| 1/2-13 | .5000 | 27/64 |
| 1/2-20 | .5000 | 29/64 |
| 9/16-12 | .5625 | 31/64 |
| 9/16-18 | .5625 | 33/64 |
| 5/8-11 | .6250 | 17/32 |
| 5/8-18 | .6250 | 37/64 |
| 3/4-10 | .7500 | 21/32 |
| 3/4-16 | .7500 | 11/16 |
| 7/8-9 | .8750 | 49/64 |
| 7/8-14 | .8750 | 13/16 |
| 1-8 | 1.0000 | 7/8 |
| 1-14 | 1.0000 | 15/16 |
| 1-1/8-7 | 1.1250 | 63/64 |
| 1-1/8-12 | 1.1250 | 1-3/64 |
Coarse series shown in bold
Closest size for 75% theoretical thread.
| Thread Size | Basic Major Dia. | Tap Drill Size |
|---|---|---|
| M1.6x0.35 | .0630 | 1.25mm or #55 |
| M2x0.4 | .0787 | 1.60mm or #52 |
| M2.5x0.45 | .0984 | 2.05mm or #46 |
| M3x0.5 | .1181 | 2.50mm or #39 |
| M3.5x0.6 | .1378 | 2.90mm or #32 |
| M4x0.7 | .1575 | 3.30mm or #30 |
| M5x0.8 | .1969 | 4.20mm or #19 |
| M6x1 | .2362 | 5.00mm or #8 |
| M8x1.25 | .3150 | 6.80mm or H |
| M8x1 | .3150 | 7.00mm or J |
| M10x1.5 | .3937 | 8.50mm or R |
| M10x1.25 | .3937 | 8.80mm or 11/32 |
| M12x1.75 | .4724 | 10.20mm or 13/32 |
| M12x1.25 | .4724 | 10.80mm or 27/64 |
| M14x2 | .5512 | 12.00mm or 15/32 |
| M14x1.5 | .5512 | 12.50mm or 1/2 |
| M16x2 | .6299 | 14.00mm or 35/64 |
| M16x1.5 | .6299 | 14.50mm or 37/64 |
| M18x2.5 | .7087 | 15.50mm or 39/64 |
| M18x1.5 | .7087 | 16.50mm or 21/32 |
| M20x2.5 | .7874 | 17.50mm or 11/16 |
| M20x1.5 | .7874 | 18.50mm or 47/64 |
| M22x2.5 | .8661 | 19.50mm or 49/64 |
| M22x1.5 | .8661 | 20.50mm or 13/16 |
| M24x3 | .9449 | 21.00mm or 53/64 |
| M24x2 | .9449 | 22.00mm or 7/8 |
| M27x3 | 1.0630 | 24.00mm or 15/16 |
| M27x2 | 1.0630 | 25.00mm or 1 |
Coarse series shown in bold
Closest size for 75% theoretical thread.