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#18 drill bit size
#18 drill = .1695 in = 4.30 mm. Closest metric drill: 4.3 mm.
Nearby drill sizes
| Drill | Type | Inch | mm | Difference |
|---|---|---|---|---|
| #22 | number | .1570 in | 3.988 | -12.5 thou |
| #21 | number | .1590 in | 4.039 | -10.5 thou |
| #20 | number | .1610 in | 4.089 | -8.5 thou |
| #19 | number | .1660 in | 4.216 | -3.5 thou |
| #18 | number | .1695 in | 4.305 | 0.0 thou |
| 11/64 | fraction | .1719 in | 4.366 | 2.4 thou |
| #17 | number | .1730 in | 4.394 | 3.5 thou |
| #16 | number | .1770 in | 4.496 | 7.5 thou |
| #15 | number | .1800 in | 4.572 | 10.5 thou |
1 thou = 0.001 in = 0.0254 mm. Drills a few thou apart are usually interchangeable for clearance holes, but not for tap drills or reamer pilots.