Bolt Spanner Size Chart

Below you will find a chart explaining the sizing of bolts and nuts complete with the basic sizing for which spanner fits which bolt. The table below covers Wrench and Hex sizes both in inches and in millimeters to ensure that no matter where you find yourself in the world you can obtain the information you need to make an informed decision on the subject of bolt sizing.


Wrench Sizes (in.)

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The table above shows the diameter of the bolt with the size of both the hex and the heavy hex measured in inches. A heavy hex nut is exactly 1/8 inches larger across the flats than a normal hex nut. This means you need a 1/8 inches larger wrench or socket to be able to install this nut. They also have a higher load strength than a normal hex nut.


Wrench & Hex Key Sizes (mm)

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The above table shows the diameter, hex – and socket size as measured in millimeters. This gives a clear indication of the relevant sizings for each standard bolt diameter.



See also  External Torx Size Chart