convertimate Drill bit sizes

Letter drill to millimeters

Type a value in letter drill to get it in mm instantly.

6.629mm

That's 1.02× as wide as the tap drill for 5/16-18 (F), while the tap drill for 3/8-16 (5/16") is 1.2× wider.

What it means

How wide is that hole?

Sizes from ASME B94.11M. Between two listed drills the label shows the nearest one; the millimeters are exact.

The math

How to convert letter drill to mm

Number and letter drills are a table: #29 = 0.1360 in = 3.454 mm, #7 = 0.2010 in, F = 0.2570 in. Millimeters = inches × 25.4.

Example: G letter drill = 6.6294 mm.

Every unit

That drill in every system

Tables

letter drill to mm conversion table

letter drill to mm conversion table
letter drillmm
A letter drill5.9436 mm
C letter drill6.1468 mm
E letter drill6.35 mm
G letter drill6.6294 mm
J letter drill7.0358 mm
O letter drill8.0264 mm
T letter drill9.0932 mm
U letter drill9.3472 mm
Y letter drill10.2616 mm
mm to letter drill conversion table
mm to letter drill conversion table
mmletter drill
6.15 mmC letter drill
6.35 mmE letter drill
6.63 mmG letter drill
7.04 mmJ letter drill
8.03 mmO letter drill
9.09 mmT letter drill
9.35 mmU letter drill
10.3 mmY letter drill

Quick answers

Quick answers

How many mm is A letter drill?
A letter drill is 5.9436 mm.
How many mm is J letter drill?
J letter drill is 7.0358 mm.
How many mm is G letter drill?
G letter drill is 6.6294 mm.

The units

About these units

Letter drill (letter drill)

Letter drills A to Z.

Millimeters (mm)

The diameter in millimeters, as metric drills are sold.

Learn more about drill size units

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