Screw
Size		 Decimal 
Equiv. 
(Inches)		 Hex
Key Size
(Inches)		 Head
Height
(Inches)		 Head
Diameter
(Inches)
No. 0
 0.060 0.050 0.060 0.096
No. 1
 0.073 1/16 0.073 0.118
No. 2
 0.086 5/64 0.086 0.140
No. 3
 0.099 5/64 0.099 0.161
No. 4
 0.112 3/32 0.112 0.183
No. 5
 0.125 3/32 0.125 0.205
No. 6
 0.138 7/64 0.138 0.226
No.  8
 0.164 9/64 0.164 0.270
No. 10
 0.190 5/32 0.190 0.312
No. 12
 0.216 5/32 0.216 ???
1/4" 0.250 3/16 1/4 3/8
5/16" 0.313 1/4 5/16 15/32
3/8" 0.375 5/16 3/8 9/16
7/16" 0.438 3/8 7/16 21/32
1/2" 0.500 3/8 1/2 3/4
5/8" 0.625 1/2 5/8 15/16
3/4" 0.750 5/8 3/4 1 1/8
7/8" 0.875 3/4 7/8 1 5/16
1" 1.000 3/4 1 1 1/2
1 1/8" 1.125 7/8 1 1/8 1 11/16
Socket Head Cap Screw Key Size Chart
DIN 912 - 1983  ISO / 4762 - 1989
Screw
Size		 Hex
Key Size
MM		 Head
Height
MM 		Head
Diameter
MM
M 1.6
 1.5 1.7 3
M 2
 1.5 1.5 3.5
M 2.5
 2.0 2.0 4.5
M 3
 2.5 2.5 5.5
M 4
 3.0 3.0 7
M 5
 4.0 4.0 8.5
M 6
 5.0 5.0 10
M 8
 6.0 6.0 13
M 10
 8.0 8.0 16
M 12
 10 10 18

M 14

 12 12 21
M 16 14 14 24
M 18 14 18 27
M 20 17 20 30
M 22 17 122 33
M 24 19 24 36
M27 19 27 40
M 30 22 30 45
M 33 24 33 50
M 36 27 36 54