Letter Drills

This system of numbering drills is no longer used, but may be of use in deciphering old drawings.

Letter

Diameter inches

Letter

Diameter inches

Letter

Diameter inches

Letter

Diameter inches

A

0.234

H

0.266

O

0.316

V

0.377

B

0.238

I

0.272

P

0.323

W

0.386

C

0.242

J

0.277

Q

0.332

X

0.397

D

0.246

K

0.281

R

0.339

Y

0.404

E

0.250

L

0.290

S

0.348

Z

0.413

F

0.257

M

0.295

T

0.358

 

 

G

0.261

N

0.302

U

0.368

 

 


See also: Drill Bits, Number Drills.

Previous PageView links to and from this pageNext Page

Subjects: Tools