# #49 drill size

A #49 drill is 0.0730 in (1.85 mm). It sits between #50 and #48 in the number series; the nearest metric drill is 1.85 mm.

## #49 drill data

- Series: Number drill
- Decimal: 0.0730 in
- Metric: 1.85 mm (1.8542 mm exact)
- Nearest metric drill: 1.85 mm (−0.004 mm)
- Nearest fractional: 5/64" (0.0781 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 1.85 mm | 0.0728 | −0.004 mm |
| 1.9 mm | 0.0748 | +0.046 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 1/16" | Fractional | 0.0625 | 1.59 |
| #50 | Number | 0.0700 | 1.78 |
| #49 | Number | 0.0730 | 1.85 |
| #48 | Number | 0.0760 | 1.93 |
| 5/64" | Fractional | 0.0781 | 1.98 |
| Letter A | Letter | 0.2340 | 5.94 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| #2-64 UNF | #50 | 64 |
| #2-56 UNC | #50 | 56 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| M1.6 bolt | 1.6 mm | 0.25 mm | 0.13 mm | Normal fit (normal 1.8, loose 2 mm) |


## FAQ

**What size is a #49 drill?**
A #49 drill is 0.0730 in, which is 1.85 mm (1.8542 mm exactly).

**What is the metric equivalent of a #49 drill?**
The nearest metric drill is 1.85 mm, 0.004 mm smaller. The other close size is 1.9 mm.

**What thread can I tap with a #49 drill?**
It leaves about 64 % thread in #2-64 UNF and 56 % in #2-56 UNC.

**Which fractional drill is closest to #49?**
5/64 in (0.0781 in) is the closest, 0.0051 in larger.

**What does a #49 drill clear?**
It clears a M1.6 bolt with 0.25 mm total clearance (0.13 mm per side); for metric bolts: normal fit.

Source page: https://machinistcharts.com/drill-size/number-49/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)