Drive Sizes for US Allen Drive Screws

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Screw Diameter

Drive Size
Socket flat head screw
Socket Flat 		Socket button head screw
Socket Button 		Socket cap screw
Socket Cap 		Socket set screw
Set Screw
#0 0.89mm (0.035") 0.89mm (0.035") 1.27mm (0.050") 0.71mm (0.028")
#1 1.27mm (0.050") 1.27mm (0.050") 1/16" 0.89mm (0.035")
#2 1.27mm (0.050") 1.27mm (0.050") 5/64" 0.89mm (0.035")
#3 1/16" 1/16" 5/64" 1.27mm (0.050")
#4 1/16" 1/16" 3/32" 1.27mm (0.050")
#5 5/64" 5/64" 3/32" 1/16"
#6 5/64" 5/64" 7/64" 1/16"
#8 3/32" 3/32" 9/64" 5/64"
#10 1/8" 1/8" 5/32" 3/32"
#12 1/8" * 5/32" 3/32"
1/4" 5/32" 5/32" 3/16" 1/8"
5/16" 3/16" 3/16" 1/4" 5/32"
3/8" 7/32" 7/32" 5/16" 3/16"
7/16" 1/4" 1/4" 3/8" 7/32"
1/2" 5/16" 5/16" 3/8" 1/4"
9/16" * * 7/16" 1/4"
5/8" 3/8" 3/8" 1/2" 5/16"
3/4" 1/2" 7/16" 5/8" 3/8"
7/8" 9/16" 3/4" 1/2"
1" 5/8" 3/4" 9/16"
1-1/8" 3/4"   7/8"
1-1/4" 7/8"   7/8"
1-3/8" 7/8"   1"
1-1/2" 1"   1"
* This product is not manufactured, or does not have a standardized drive size.