PROTO, Industrial Tools

Phone: 800-800-TOOL

Conversion Charts


BOLT SIZING CHART

Nominal Opening of Proto Wrenches or Sockets in Millimeters
to Fit Standard Nuts


Locate thread diameter of nut in left column. Then move across to box which has proper identification of nut 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 NUTS
HEX NUTS
STYLE 1
HEX NUTS
STYLE 2
SLOTTED AND HAM HEX NUTS
HEAVY HEX BOLTS
 
Use wrench or socket size shown below
M1.6 x 0.35
3.20
M2 x 0.4
4.00
M2.5 x 0.45
5.00
M3 x 0.5
5.50
5.50
M3.5 x 0.6
6.00
6.00
M4 x 0.7
7.00
7.00
M5 x 0.8
8.00
8.00
8.00
M6 x 1
10.00
10.00
10.00
M8 x 1.25
13.00
13.00
13.00
M10 x 1.5
15.00 & 16.00
15.00 & 16.00
15.00 & 16.00
M12 x 1.75
18.00
18.00
18.00
21.00
M14 x 2
21.00
21.00
21.00
24.00
M16 x 2
24.00
24.00
24.00
27.00
M20 x 2.5
30.00
30.00
30.00
34.00
M22 x 2.5
36.00
M24 x 3
36.00
36.00
36.00
41.00
M27 x 3
46.00
M30 x 3.5
46.00
46.00
46.00
50.00
M36 x 4
55.00
55.00
55.00
60.00
M42 x 4.5
70.00
M48 x 5
80.00
M56 x 5.5
90.00
M64 x 6
100.00
M72 x 6
110.00
M80 x 6
120.00
M90 x 6
135.00
M100 x 6
150.00