# 23/64" drill size

A 23/64 in drill is 0.3594 in (9.13 mm). It sits between 11/32 in and 3/8 in in the fractional series; the nearest metric drill is 9.1 mm.

## 23/64" drill data

- Series: Fractional drill
- Decimal: 0.3594 in
- Metric: 9.13 mm (9.1281 mm exact)
- Nearest metric drill: 9.1 mm (−0.028 mm)
- Nearest letter drill: Letter T (0.3580 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 9.1 mm | 0.3583 | −0.028 mm |
| 9.2 mm | 0.3622 | +0.072 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| 11/32" | Fractional | 0.3438 | 8.73 |
| Letter T | Letter | 0.3580 | 9.09 |
| 23/64" | Fractional | 0.3594 | 9.13 |
| Letter U | Letter | 0.3680 | 9.35 |
| 3/8" | Fractional | 0.3750 | 9.52 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| M10 × 1 | 9 mm | 67 |
| 7/16-14 UNC | U | 84 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| 5/16" bolt | 0.3125" | 0.0469" | 0.0234" | – |
| M8 bolt | 8 mm | 1.13 mm | 0.56 mm | Normal fit (normal 9, loose 10 mm) |


## FAQ

**What size is a 23/64 in drill?**
A 23/64 in drill is 0.3594 in, which is 9.13 mm (9.1281 mm exactly).

**What is the metric equivalent of a 23/64 in drill?**
The nearest metric drill is 9.1 mm, 0.028 mm smaller. The other close size is 9.2 mm.

**What thread can I tap with a 23/64 in drill?**
It leaves about 67 % thread in M10 × 1 and 84 % in 7/16-14 UNC.

**Which number or letter drill is closest to 23/64 in?**
Letter T (0.3580 in) is the closest, 0.0014 in smaller.

**What does a 23/64 in drill clear?**
It clears a M8 bolt with 1.13 mm total clearance (0.56 mm per side); for metric bolts: normal fit.

Source page: https://machinistcharts.com/drill-size/23-64-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)