A #49 drill measures 0.0730 inch (1.854 mm). The closest fractional drill is 5/64" (0.0781") and the closest metric drill is 1.9 mm (0.0748").
What are the #49 drill equivalents?
| Drill | System | Decimal (in) | mm | Difference (in) |
|---|---|---|---|---|
| #49 | number | 0.0730 | 1.854 | 0 |
| #50 | number | 0.0700 | 1.778 | -0.0030 |
| 1.8 mm | metric | 0.0709 | 1.800 | -0.0021 |
| 1.9 mm | metric | 0.0748 | 1.900 | +0.0018 |
Drill sets that include this size
Number and letter sizes come in indexed sets; buy the set rather than single drills.
What speed should a #49 drill run?
| Material | RPM (HSS) | Feed (in/rev) |
|---|---|---|
| 6061-T6 aluminum | 10,465 | 0.0015 |
| 360 free-machining brass | 7,849 | 0.0013 |
| 1018 cold rolled steel | 4,186 | 0.0011 |
| 304 stainless steel | 2,093 | 0.0007 |
Starting points from conservative HSS drilling speeds. Small drills often call for more RPM than a benchtop drill press offers; run at the top speed and feed gently. Use cutting oil in steel and stainless, and clamp the work: never hold it by hand.
Cutting fluid for drilling
Frequently asked questions
What is a #49 drill in inches?
0.0730 inch, which is 1.854 mm. Number drills get smaller as the number rises, so the next number up is a smaller drill. If you do not have this exact size, 1.9 mm is within 0.0018 inch.
What tap uses a #49 drill?
No common UNC or UNF thread uses it as its standard 75% tap drill, but it often serves as an alternative drill for a slightly different percentage of thread, or as a clearance or pilot size. The tap drill chart lists every standard pairing.