# 17/64" drill size

A 17/64 in drill is 0.2656 in (6.75 mm). It sits between 1/4 in and 9/32 in in the fractional series; the nearest metric drill is 6.7 mm.

## 17/64" drill data

- Series: Fractional drill
- Decimal: 0.2656 in
- Metric: 6.75 mm (6.7469 mm exact)
- Nearest metric drill: 6.7 mm (−0.047 mm)
- Nearest letter drill: Letter H (0.2660 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 6.7 mm | 0.2638 | −0.047 mm |
| 6.8 mm | 0.2677 | +0.053 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| 1/4" | Fractional | 0.2500 | 6.35 |
| Letter G | Letter | 0.2610 | 6.63 |
| 17/64" | Fractional | 0.2656 | 6.75 |
| Letter H | Letter | 0.2660 | 6.76 |
| 9/32" | Fractional | 0.2812 | 7.14 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| M8 × 1.25 | 6.8 mm | 77 |
| 5/16-18 UNC | F | 65 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| #12 screw | 0.2160" | 0.0496" | 0.0248" | – |
| M6 bolt | 6 mm | 0.75 mm | 0.37 mm | Normal fit (normal 6.6, loose 7 mm) |
| 1/4" bolt | 0.2500" | 0.0156" | 0.0078" | – |


## FAQ

**What size is a 17/64 in drill?**
A 17/64 in drill is 0.2656 in, which is 6.75 mm (6.7469 mm exactly).

**What is the metric equivalent of a 17/64 in drill?**
The nearest metric drill is 6.7 mm, 0.047 mm smaller. The other close size is 6.8 mm.

**What thread can I tap with a 17/64 in drill?**
It leaves about 77 % thread in M8 × 1.25 and 65 % in 5/16-18 UNC.

**Which number or letter drill is closest to 17/64 in?**
Letter H (0.2660 in) is the closest, 0.0004 in larger.

**What does a 17/64 in drill clear?**
It clears a 1/4" bolt with 0.0156" total clearance (0.0078" per side).

Source page: https://machinistcharts.com/drill-size/17-64-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)