Drill Bit, Purchase Guide

Drill Bit Size Chart

26
Jul

When using a drill bit for a feeler gauge, please remember that many drill bits are actually undersized at the shank end of the drill bit, so please use the above bit sizes with a grain of salt!

Also, note that to correct for a broad feeler gauge or a loose-fitting drill bit:

 

ROC = (D2-W2)/8T

Where:

  • D = mirror diameter,
  • W = the width of the feeler gauge, or if the drill bit can be moved back and forth under the straight edge by the total amount W
  • T = gauge thickness, or bit diameter.

Drill sizes to 1″ diameter

Legend
Fractional Inch
Letter Drill
Millimeters
Number Drill
Millimeters
Inches
Designation
Tap Drill/Pilot Drill Uses
.3429mm.0135″#80
.3683mm.0145″#79
.3969mm.015625″1/64″#0 Pilot, Soft-Wood
.4064mm.016″#78
.4572mm.018″#77
.5mm.0197″
.508mm.02″#76
.5334mm.021″#75
.5715mm.0225″#74
.6096mm.024″#73
.635mm.025″#72
.6604mm.026″#71
.7112mm.028″#70
.74168mm.0292″#69
.75mm.0295″M1x.25 coarse
.7874mm.031″#68
.7938mm.03125″1/32″#0 Pilot, Hard-Wood #1 Pilot, Hard & Soft-Wood #2 Pilot, Soft-Wood
.8128mm.032″#67
.8382mm.033″#66
.85mm.0335″M1.1x.25 coarse
.889mm.035″#65
.9144mm.036″#64
.9398mm.037″#63
.95mm.0374″M1.2x.25 coarse
.9652mm.038″#62
.9906mm.039″#61
1mm.0394″
1.016mm.04″#60
1.0414mm.041″#59
1.0668mm.042″#58
1.0922mm.043″#57
1.1mm.0433″M1.4x.3 coarse
1.1811mm.0465″#56
1.1906mm.046875″3/64″#0-80 UNF#2 Pilot, Hard-wood, #3 Pilot, Soft-Wood #4 Pilot, Soft-Wood
1.25mm.0492″M1.6x.35 coarse
1.3mm.0512″M1.7x.35 coarse
1.3208mm.052″#55
1.397mm.055″#54
1.45mm.0571″M1.8x.35 coarse
1.5mm.0591″
1.5113mm.0595″#53#1-64 UNC, #1-72 UNF
1.5875mm.0625″1/16″#0 Wood Shank Hole, #3 Pilot, Hard-Wood, #4 Pilot, Hard-wood #5 Pilot, Soft-wood, #6 Pilot, Soft-wood, #7 Pilot, Soft-wood
1.6mm.063″M2x.4 coarse
1.6129mm.0635″#52
1.7018mm.067″#51
1.75mm.0689″M2.2x.45 coarse
1.778mm.07″#50#2-64 UNF, #2-56 UNC
1.8542mm.073″#49
1.9304mm.076″#48
1.9844mm.078125″5/64″#1 Wood Shank Hole#5 Pilot, Hard-wood, #6 Pilot, Hard-wood #8 Pilot, Soft-wood, #9 Pilot, Soft-wood
1.9939mm.0785″#47#3-48 UNC
2mm.0787″
2.05mm.0807″M2.5x.45 coarse
2.0574mm.081″#46
2.0828mm.082″#45#3-56 UNF
2.1844mm.086″#44
2.2606mm.089″#43#4-40 UNC
2.3749mm.0935″#42#4-48 UNF
2.3813mm.09375″3/32″#2 Wood Shank Hole, #7 Pilot, Hard-wood, #8 Pilot, Hard-wood, #10 Pilot, Soft-wood, #11 Pilot, Soft-wood
2.4384mm.096″#41
2.4892mm.098″#40
2.5mm.0984″M3x.5 coarse
2.5273mm.0995″#39
2.5781mm.1015″#38#5-40 UNC
2.6416mm.104″#37#5-44 UNF
2.7051mm.1065″#36#6-32 UNC
2.7781mm.109375″7/64″#3 Wood Shank Hole, #4 Wood Shank Hole, #9 Pilot, Hard-wood #10 Pilot, Hard-wood, #12 Pilot, Soft-wood, #14 Pilot, Soft-wood
2.794mm.11″#35
2.8194mm.111″#34
2.8702mm.113″#33#6-40 UNF
2.9mm.1142″M3.5x.6 coarse
2.9464mm.116″#32
3mm.1181″
3.048mm.12″#31
3.175mm.125″1/8″#5 Wood Shank Hole, #11 Pilot, Hard-wood, #12 Pilot, Hard-wood
3.2639mm.1285″#30
3.3mm.1299″M4x.7 coarse
3.4544mm.136″#29#8-32 UNC, #8-36 UNF
3.5mm.1378″M4x.5 Fine
3.5687mm.1405″#28
3.5719mm.140625″9/64″#6 Wood Shank Hole, #14 Pilot, Hard-wood, #16 Pilot, Soft-wood #18 Pilot, Soft-wood
3.6mm.1417″M4x.35 Fine
3.6576mm.144″#27
3.7mm.1457″M4.5x.75 coarse
3.7338mm.147″#26
3.7973mm.1495″#25#10-24 UNC
3.8608mm.152″#24
3.9116mm.154″#23
3.9688mm.15625″5/32″#7 Wood Shank Hole, #16 Pilot, Hard-wood
3.9878mm.157″#22
4mm.1575″
4.0386mm.159″#21#10-32 UNF
4.0894mm.161″#20
4.2mm.1654″M5x.8 coarse
4.2164mm.166″#19
4.3053mm.1695″#18
4.3656mm.171875″11/64″#8 Wood Shank Hole, #20 Pilot, Soft-wood
4.3942mm.173″#17#12-24 UNC
4.4958mm.177″#16
4.5mm.1772″M5x.5 Fine
4.572mm.18″#15#12-28 UNF
4.6228mm.182″#14
4.699mm.185″#13
4.7625mm.1875″3/16″#9 Wood Shank Hole, #10 Wood Shank Hole, #18 Pilot, Hardwood
4.8006mm.189″#12
4.8514mm.191″#11
4.9149mm.1935″#10
4.9784mm.196″# 9
5mm.1969″M6x1 coarse
5.0546mm.199″# 8
5.1054mm.201″# 71/4″-20 UNC
5.1594mm.203125″13/64″#11 Wood Shank Hole, #20 Pilot, Hard-wood
5.1816mm.204″# 6
5.2197mm.2055″# 5
5.25mm.2067″M6x.75 Fine
5.3086mm.209″# 4
5.4102mm.213″# 31/4″-28 UNF
5.5mm.2165″M6x.5 Fine
5.5563mm.21875″7/32″#12 Wood Shank Hole
5.6134mm.221″# 2
5.7912mm.228″# 1
5.9436mm.234″A
5.9531mm.234375″15/64″
6mm.2362″M7x1 coarse
6.0452mm.238″B
6.1468mm.242″C
6.2484mm.246″D1/16″-27 NPT
6.25mm.2461″M7x.75 Fine
6.35mm.25″1/4″#14 Wood Shank Hole
6.35mm.25″E
6.5mm.2559″
6.5278mm.257″F5/16″-18 UNC
6.6294mm.261″G
6.7469mm.265625″17/64″#16 Wood Shank Hole
6.7564mm.266″H
6.8mm.2677″M8x1.25 coarse
6.9088mm.272″I5/16″-24 UNF
7mm.2756″M8x.5 Fine
7.0358mm.277″J
7.1374mm.281″K
7.1438mm.28125″9/32″
7.25mm.2854″M8x.75 Fine
7.366mm.29″L
7.493mm.295″M
7.5mm.2953″M8x1 Fine
7.5406mm.296875″19/64″#18 Wood Shank Hole
7.6708mm.302″N
7.8mm.3071″M9x1.25 coarse
7.9375mm.3125″5/16″3/8″-16 UNC
8mm.315″M9x1 Fine
8.0264mm.316″O
8.2042mm.323″P
8.3344mm.328125″21/64″#20 Wood Shank Hole
8.4328mm.332″Q3/8″-24 UNF
8.5mm.3346″M10x1.5 coarse
8.6106mm.339″R1/8″-27 NPT
8.7313mm.34375″11/32″
8.8mm.3465″M10x1.25 Fine
8.8392mm.348″S
9mm.3543″M10x1 Fine
9.0932mm.358″T7/16″-14 UNC
9.1281mm.359375″23/64″
9.25mm.3642″M10x.75 Fine
9.3472mm.368″U
9.5mm.374″M11x1.5 coarse
9.525mm.375″3/8″
9.5758mm.377″V
9.8044mm.386″W
9.9219mm.390625″25/64″7/16″-20 UNF
10mm.3937″M11x1 Fine
10.0838mm.397″X
10.2mm.4016″M12x1.75 coarse
10.2616mm.404″Y
10.3188mm.40625″13/32″
10.4902mm.413″Z
10.5mm.4134″M12x1.5 Fine
10.7156mm.421875″27/64″1/2″-13 UNC
11mm.4331″M12x1 Fine
11.1125mm.4375″7/16″1/4″-18 NPT
11.25mm.4429″M12x.75 Fine
11.5mm.4528″
11.5094mm.453125″29/64″1/2″-20 UNF
11.9063mm.46875″15/32″
12mm.4724″M14x2 coarse
12.3031mm.484375″31/64″9/16″-12 UNC
12.5mm.4921″M14x1.5 Fine
12.7mm.5″1/2″
12.8mm.5039″M14x1.25 Fine
13mm.5118″M14x1 Fine
13.0969mm.515625″33/64″9/16″-18 UNF
13.4938mm.53125″17/32″5/8″-11 UNC
13.5mm.5315″
13.8906mm.546875″35/64″
14mm.5512″M16x2 coarse
14.2875mm.5625″9/16″5/8″-18 UNF
14.5mm.5709″M16x1.5 Fine
14.6844mm.578125″37/64″3/8″-18 NPT
15mm.5906″M16x1 Fine
15.0813mm.59375″19/32″
15.4781mm.609375″39/64″
15.5mm.6102″M18x2.5 coarse
15.875mm.625″5/8″
16mm.6299″M18x2 Fine
16.2719mm.640625″41/64″3/4″-10 UNC
16.5mm.6496″
16.6688mm.65625″21/32″
17mm.6693″M18x1 Fine
17.0656mm.671875″43/64″
17.4625mm.6875″11/16″3/4″-16 UNF
17.5mm.689″M20x2.5 coarse
17.8594mm.703125″45/64″1/2″-14 NPT
18mm.7087″M20x2 Fine
18.2563mm.71875″23/32″
18.5mm.7283″M20x1.5 Fine
18.6531mm.734375″47/64″
19mm.748″M20x1 Fine
19.05mm.75″3/4″
19.4469mm.765625″49/64″7/8″-9 UNC
19.5mm.7677″M22x2.5 coarse
19.8438mm.78125″25/32″
20mm.7874″M22x2 Fine
20.2406mm.796875″51/64″
20.5mm.8071″M22x1.5 Fine
20.6375mm.8125″13/16″7/8″-14 UNF
21mm.8268″M24x3 coarseM22x1 Fine
21.0344mm.828125″53/64″
21.4313mm.84375″27/32″
21.5mm.8465″
21.8281mm.859375″55/64″
22mm.8661″M24x2 Fine
22.225mm.875″7/8″1″-8 UNC
22.5mm.8858″M24x1.5 Fine
22.6219mm.890625″57/64″
23mm.9055″
23.0188mm.90625″29/32″1″-12 UNF
23.4156mm.921875″59/64″3/4″-14 NPT
23.5mm.9252″
23.8125mm.9375″15/16″
24mm.9449″M27x3 coarse
24.2094mm.953125″61/64″
24.5mm.9646″M26x1.5 Fine
24.6063mm.96875″31/32″
25mm.9843″M27x2 Fine
25.0031mm.984375″63/64″1-1/8″-7 UNC
25.4mm1.000″1″
Olivia E. Madison
Author: Olivia E. Madison

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