# #33 drill size

A #33 drill is 0.1130 in (2.87 mm). It is the standard tap drill for #6-40 UNF; the nearest metric drill is 2.85 mm.

## #33 drill data

- Series: Number drill
- Decimal: 0.1130 in
- Metric: 2.87 mm (2.8702 mm exact)
- Nearest metric drill: 2.85 mm (−0.020 mm)
- Nearest fractional: 7/64" (0.1094 in)
- Standard tap drill for: #6-40 UNF

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 2.85 mm | 0.1122 | −0.020 mm |
| 2.9 mm | 0.1142 | +0.030 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 7/64" | Fractional | 0.1094 | 2.78 |
| #34 | Number | 0.1110 | 2.82 |
| #33 | Number | 0.1130 | 2.87 |
| #32 | Number | 0.1160 | 2.95 |
| 1/8" | Fractional | 0.1250 | 3.17 |
| Letter A | Letter | 0.2340 | 5.94 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| #6-40 UNF | #33 | 77 |
| M3.5 × 0.6 | 2.9 mm | 81 |
| #6-32 UNC | #36 | 62 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| #1 screw | 0.0730" | 0.0400" | 0.0200" | – |
| #2 screw | 0.0860" | 0.0270" | 0.0135" | – |
| M2.5 bolt | 2.5 mm | 0.37 mm | 0.19 mm | Close fit (close 2.7, normal 2.9 mm) |
| #3 screw | 0.0990" | 0.0140" | 0.0070" | – |
| #4 screw | 0.1120" | 0.0010" | 0.0005" | – |


## FAQ

**What size is a #33 drill?**
A #33 drill is 0.1130 in, which is 2.87 mm (2.8702 mm exactly).

**What is the metric equivalent of a #33 drill?**
The nearest metric drill is 2.85 mm, 0.020 mm smaller. The other close size is 2.9 mm.

**What tap uses a #33 drill?**
A #33 drill is the standard tap drill for #6-40 UNF (about 77 % thread).

**Which fractional drill is closest to #33?**
7/64 in (0.1094 in) is the closest, 0.0036 in smaller.

**What does a #33 drill clear?**
It clears a #4 screw with 0.0010" total clearance (0.0005" per side).

Source page: https://machinistcharts.com/drill-size/number-33/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)