# 47/64" drill size

A 47/64 in drill is 0.7344 in (18.65 mm). It sits between 23/32 in and 3/4 in in the fractional series; the nearest metric drill is 18.7 mm.

## 47/64" drill data

- Series: Fractional drill
- Decimal: 0.7344 in
- Metric: 18.65 mm (18.6531 mm exact)
- Nearest metric drill: 18.7 mm (+0.047 mm)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 18.6 mm | 0.7323 | −0.053 mm |
| 18.7 mm | 0.7362 | +0.047 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| Letter Z | Letter | 0.4130 | 10.49 |
| 23/32" | Fractional | 0.7188 | 18.26 |
| 47/64" | Fractional | 0.7344 | 18.65 |
| 3/4" | Fractional | 0.7500 | 19.05 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| M20 × 1.5 | 18.5 mm | 69 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| M18 bolt | 18 mm | 0.65 mm | 0.33 mm | Tighter than close fit (19 mm) |


## FAQ

**What size is a 47/64 in drill?**
A 47/64 in drill is 0.7344 in, which is 18.65 mm (18.6531 mm exactly).

**What is the metric equivalent of a 47/64 in drill?**
The nearest metric drill is 18.7 mm, 0.047 mm larger. The other close size is 18.6 mm.

**What thread can I tap with a 47/64 in drill?**
It leaves about 69 % thread in M20 × 1.5.

**What does a 47/64 in drill clear?**
It clears a M18 bolt with 0.65 mm total clearance (0.33 mm per side); for metric bolts: tighter than close fit.

Source page: https://machinistcharts.com/drill-size/47-64-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)