# 43/64" drill size

A 43/64 in drill is 0.6719 in (17.07 mm). It sits between 21/32 in and 11/16 in in the fractional series; the nearest metric drill is 17.1 mm.

## 43/64" drill data

- Series: Fractional drill
- Decimal: 0.6719 in
- Metric: 17.07 mm (17.0656 mm exact)
- Nearest metric drill: 17.1 mm (+0.034 mm)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 17.0 mm | 0.6693 | −0.066 mm |
| 17.1 mm | 0.6732 | +0.034 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| Letter Z | Letter | 0.4130 | 10.49 |
| 21/32" | Fractional | 0.6562 | 16.67 |
| 43/64" | Fractional | 0.6719 | 17.07 |
| 11/16" | Fractional | 0.6875 | 17.46 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| 3/4-10 UNC | 21/32 | 60 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| 5/8" bolt | 0.6250" | 0.0469" | 0.0234" | – |
| M16 bolt | 16 mm | 1.07 mm | 0.53 mm | Close fit (close 17, normal 17.5 mm) |


## FAQ

**What size is a 43/64 in drill?**
A 43/64 in drill is 0.6719 in, which is 17.07 mm (17.0656 mm exactly).

**What is the metric equivalent of a 43/64 in drill?**
The nearest metric drill is 17.1 mm, 0.034 mm larger. The other close size is 17.0 mm.

**What thread can I tap with a 43/64 in drill?**
It leaves about 60 % thread in 3/4-10 UNC.

**What does a 43/64 in drill clear?**
It clears a M16 bolt with 1.07 mm total clearance (0.53 mm per side); for metric bolts: close fit.

Source page: https://machinistcharts.com/drill-size/43-64-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)