Hexagon bolts have a six sided head to provide installation via a socket wrench. They are used for fastening together numerous types of material or to be fastened into pre-tapped holes. Widely used in many engineering applications.
These bolts are partially threaded as the shank allows for a stronger fastener. On metric bolts, the thread on a bolt can be calculated by multiplying the diameter by 2, and then adding 6mm on lengths under 120mm, or 12mm on longer lengths.
Zinc coatings prevent oxidation of the protected metal to create a longer lasting finish. It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged. Zinc oxide is a fine white dust that (in contrast to iron oxide) does not trigger a breakdown of the substrates surface integrity as it is formed. The zinc oxide, if left intact, can act as a barrier to further oxidation, in a way similar to the protection afforded to aluminium and stainless steels by their oxide layers.