Hexagon bolts are like their friends the hexagon set screws (hexagon shaped head) but they are not threaded all the way along. This means that they are not available in certain smaller lengths - you would use a hex set screw instead. The first number refers to the thread size, not the size of spanner needed.
Hexagon bolts are like their friends the hexagon set screws (hexagon shaped head) but they are not threaded all the way along. This means that they are not available in certain smaller lengths - you would use a hex set screw instead. The first number refers to the thread size, not the size of spanner needed.