PROTO, Industrial Tools

Phone: 800-800-TOOL

Conversion Charts


BOLT SIZING CHART
Nominal Opening of Proto Wrenches or Sockets in Inches
to Fit Standard Bolt Heads and Screw Heads


Locate thread diameter of bolt or screw in left column. Then move across to box which has proper identification of bolt or screw at top of vertical column. The size in this particular box is the nominal opening size in inches of the PROTO wrench and sockets that will fit.

Thread Diameter
of Bolt or
of Screw
Regular and Finished Series Hex and Square Head Bolts
Heavy Series Hex and Square Head Bolts
Lag Screws
Square Head Set Screws
 
Use wrench or socket size shown below
#0 & 1
       
#2 & 3
       
#4
       
#5 & 6
       
#8
       
#10
   
5/16
3/16
#12
   
7/32
1/4"
�3/8 -1/4
 
3/8
1/4
5/16"
1/2
 
1/2
5/16
3/8"
9/16
 
9/16
3/8
7/16"
5/8
 
5/8
7/16
1/2"
3/4
7/8
3/4
1/2
9/16"
13/16
9/16
5/8"
15/16
1 1/16
15/16
5/8
3/4"
11/8
1 1/4
1 1/8
3/4
7/8"
15/16
1 7/16
1 5/16
7/8
1"
1 1/2
1 5/8
1 1/2
1
1 1/8"
1 11/16
1 13/16
1 11/16
1 1/8
1 1/4"
1 7/8
2
1 7/8
1 1/4
1 3/8"
2 1/16
2 3/16
 
1 3/8
1 1/2"
2 1/4
2 3/8
 
1 1/2
1 5/8"
2 7/16
2 9/16
   
1 3/4"
2 5/8
2 3/4
   
1 7/8"
2 13/16
2 15/16
   
2"
3
3 1/8
   
2 1/4"
3 3/8
3 1/2
   
2 1/2"
3 3/4
3 7/8
   
2 3/4"
4 1/8
4 1/4
   
3"
4 1/2
4 5/8
   
3 1/4"
4 7/8
     
3 1/2"
5 1/4
     
3 3/4"
5 5/8
     
4"
6
     
�Regular Square Bolts Only.