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Thread Sizes and Tap Drills (METRIC)
Thread
Size* |
Basic
Major
Diameter |
Tap
Drill Size** |
| M1.6x0.35 |
0.063 |
1.25mm or #55 |
| M2x0.4 |
0.0787 |
1.60mm or #52 |
| M2.5x0.45 |
0.0984 |
2.05mm or #46 |
| M3x0.5 |
0.1181 |
2.50mm or #39 |
| M3.5x0.6 |
0.1378 |
2.90mm or #32 |
| M4x0.7 |
0.1575 |
3.30mm or #30 |
| M5x0.8 |
0.1969 |
4.20mm or #19 |
| M6x1 |
0.2362 |
5.00mm or #8 |
| M8x1.25 |
0.315 |
6.8mm or H |
| M8x1 |
0.315 |
7.00mm or J |
| M10x1.5 |
0.3937 |
8.50mm or R |
| M10x1.25 |
0.3937 |
8.80mm or 11/32 |
| M12x1.75 |
0.4724 |
10.20mm or 13/32 |
| M12x1.25 |
0.4724 |
10.80mm or 27/64 |
| M14x2 |
0.5512 |
12.00mm or 15/32 |
| M14x1.5 |
0.5512 |
12.50mm or 1/2 |
| M16x2 |
0.6299 |
14.00mm or 35/64 |
| M16x1.5 |
0.6299 |
14.50mm or 37/64 |
| M18x2.5 |
0.7087 |
15.50mm or 39/64 |
| M18x1.5 |
0.7087 |
16.50mm or 21/32 |
| M20x2.5 |
0.7874 |
17.50mm or 11/16 |
| M20x1.5 |
0.7874 |
18.50mm or 47/64 |
| M22x2.5 |
0.8661 |
19.50mm or 49/64 |
| M22x1.5 |
0.8661 |
20.50mm or 13/16 |
| M24x3 |
0.9449 |
21.00mm or 53/64 |
| M24x2 |
0.9449 |
22.00mm or 7/8 |
| M27x3 |
1.063 |
24.00mm or 15/16 |
| M27x2 |
1.063 |
25.00mm or 1 |
*Coarse series shown in bold.
Pitch callout not required on metric coarse series. |
| **Closest size for 75% theoretical thread. |
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