# 61/64" drill size

A 61/64 in drill is 0.9531 in (24.21 mm). It sits between 15/16 in and 31/32 in in the fractional series; the nearest metric drill is 24.2 mm.

## 61/64" drill data

- Series: Fractional drill
- Decimal: 0.9531 in
- Metric: 24.21 mm (24.2094 mm exact)
- Nearest metric drill: 24.2 mm (−0.009 mm)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 24.2 mm | 0.9528 | −0.009 mm |
| 24.3 mm | 0.9567 | +0.091 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| Letter Z | Letter | 0.4130 | 10.49 |
| 15/16" | Fractional | 0.9375 | 23.81 |
| 61/64" | Fractional | 0.9531 | 24.21 |
| 31/32" | Fractional | 0.9688 | 24.61 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| M27 × 3 | 24 mm | 72 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| M22 bolt | 22 mm | 2.21 mm | 1.10 mm | Normal fit (normal 24, loose 26 mm) |
| M24 bolt | 24 mm | 0.21 mm | 0.10 mm | Tighter than close fit (25 mm) |


## FAQ

**What size is a 61/64 in drill?**
A 61/64 in drill is 0.9531 in, which is 24.21 mm (24.2094 mm exactly).

**What is the metric equivalent of a 61/64 in drill?**
The nearest metric drill is 24.2 mm, 0.009 mm smaller. The other close size is 24.3 mm.

**What thread can I tap with a 61/64 in drill?**
It leaves about 72 % thread in M27 × 3.

**What does a 61/64 in drill clear?**
It clears a M24 bolt with 0.21 mm total clearance (0.10 mm per side); for metric bolts: tighter than close fit.

Source page: https://machinistcharts.com/drill-size/61-64-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)