Screw To Drill Bit Size Chart

​Reference page for using the correct size ​pilot drill per screw


​​When it comes to mechanics or even body work, I prefer using a welder. However there are times when sheet metal screws are required. There is nothing more aggravating when you just don't know what size drill bit to use for a pilot. 


To help my readers out, I thought I would add this quick reference chart. This should help whenever you run into a situation you need to drill a pilot hole and are not sure the size bit.


I also have included the chart for drill bit size per tap size. In case you need to drill a hole and thread it for a screw or bolt.


Sheet Metal Screw to Drill Bit Size Table

​Screw Size

​Drill Bit Size

​2

​3/32in

​4

​1/8in

​6

​5/32in

​8

​3/16in

​10

​13/64in

​12

​1/4in

​1/4in

​9/32in

​5/16in

​21/64in

​3/8in

​25/64in

Tap and Drill Size Chart (Standard)

​Tap Size

Drill Bit

Drill Bit size inch

​0-80


​3/​64in

​1-64

53

1/16in

​1-72

​53

1/16in

​2-56

​51


​2-64

​50


​3-48


​​5/64in

​3-56

​46


​4-40

​44


​4-48

​42


​5-40

​39


​5-44

​38


​6-32

​36


​6-40

​33


​8-32

​29

9/64​

​8-36

​29

9/64​

​10-24

​25

​5/32

​10-32

​21

​5/32

​12-24

​17


​12-28

​15


​1/4-20

​7

13/64​

​1/4-28

​3

​7/32

​5/16-18

​F

1/4 - 17/64 closest Match​​

​5/16-​24

​I

​1/4 - 17/64 closest Match​​

​3/8-16


5/16​

​3/8-24

​Q


​7/16-14

​U


​7/16-20


​25/64

​1/2-13


27/64​

​1/2-20


29/64​

​9/16-12


31/64

​9/16-18


​33-64

​5/8-11


​17/32

​5/8-18


37/64​

​3/4-10


21/64​

​3/4-16


11/16​

​7/8-9


49/64​

​7/8-14


13/16​

​1-8


7/8​

​1-12


59/64​

​1-14


​15/16

​1-1/8—7


​63/64

​​1-1/8—12


​1-3/64

​​1-1/​4—7


​1-7/64

​​​1-1/​4—12


​1-11/64

​​​1-​3/8—​6


​1-7/32

​​​1-​3/8—​12


​1-19/64

​​​​1-​​1/2—​6


​1-11/32

​​​​​1-​​1/2—​12


​1-27/64

Tap and Drill Size Chart (Metric)

​Tap Size

Drill Bit

Drill Bit size

​M1.6 x .35


​1.25mm

​M2 x .4


1/16in

​M2.5 x .45


​2.05mm

​M3 x .5

​40


​M3.5 x .6

​33


​M4 x .7


​3.25mm

​M5 x .8


4.2mm​

​​M6 x 1

​10


​m8 x 1.25


6.7mm​

​M10 x 1.5

​​

8.4mm​

​M12 x 1.75


13/32in​

​M14 x 2

​​

15/32in​

​M16 x 2


35/64in​

​M20 x 2.5


​11/16in

​M24 x 3


​53/64in

​​M30 x 3.5


​1-3/64in

​M36 x 4


​1-1/4in

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