# Letter V drill size

A letter V drill is 0.3770 in (9.58 mm). It sits between letter U and letter W in the letter series; the nearest metric drill is 9.6 mm.

## Letter V drill data

- Series: Letter drill
- Decimal: 0.3770 in
- Metric: 9.58 mm (9.5758 mm exact)
- Nearest metric drill: 9.6 mm (+0.024 mm)
- Nearest fractional: 3/8" (0.3750 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 9.5 mm | 0.3740 | −0.076 mm |
| 9.6 mm | 0.3780 | +0.024 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| Letter U | Letter | 0.3680 | 9.35 |
| 3/8" | Fractional | 0.3750 | 9.52 |
| Letter V | Letter | 0.3770 | 9.58 |
| Letter W | Letter | 0.3860 | 9.80 |
| 25/64" | Fractional | 0.3906 | 9.92 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| 7/16-14 UNC | U | 65 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| M8 bolt | 8 mm | 1.58 mm | 0.79 mm | Normal fit (normal 9, loose 10 mm) |
| 3/8" bolt | 0.3750" | 0.0020" | 0.0010" | – |


## FAQ

**What size is a letter V drill?**
A letter V drill is 0.3770 in, which is 9.58 mm (9.5758 mm exactly).

**What is the metric equivalent of a letter V drill?**
The nearest metric drill is 9.6 mm, 0.024 mm larger. The other close size is 9.5 mm.

**What thread can I tap with a letter V drill?**
It leaves about 65 % thread in 7/16-14 UNC.

**Which fractional drill is closest to letter V?**
3/8 in (0.3750 in) is the closest, 0.0020 in smaller.

**What does a letter V drill clear?**
It clears a 3/8" bolt with 0.0020" total clearance (0.0010" per side).

Source page: https://machinistcharts.com/drill-size/letter-v/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)