Metallics JG8HC58214 Bolts 5/8-11 X 2-1/4 G8 Hxbt St-zn (Jar 25)

This Metallics hex bolt is Grade 8, rated 150,000 psi minimum tensile and 130,000 psi minimum yield, with a hardness of Rockwell C33-39. A Grade 5 of the same diameter is a lower tensile fastener, which is exactly why the Grade 8 gets specified for automotive and fleet work where the Grade 5 will not carry the load. It is medium carbon steel, heat treated, to AISI 1021-1045.

Head width across the flats measures 0.922 to 0.938 inch, so a 15/16 inch socket or wrench is the fit. Head height is 27/64 inch. It is a standard hex head, not a flange or socket head, so an open end wrench works where a socket will not clear.

The finish is zinc plated steel, which is a general purpose coating suited to dry or sheltered conditions and incidental moisture. For sustained outdoor exposure, salt spray, or coastal work, step up to a hot dip galvanized or stainless fastener instead. Zinc also keeps the threads running smoothly for assemblies you expect to take apart again.

It ships as a jar of 25 pieces, and 25 count is the order minimum, so the jar is the smallest unit sold. The filled jar weighs 2595 g. Other sizes and quantities in the G8HC and JG8HC series are available by request.

The JG8HC58214 is flagged both ARRA compliant and Buy American compliant in the manufacturer data. Country of origin is listed as multiple, so if your contract requires documented origin per lot, request the paperwork for the specific lot you receive.

At 5/8-11 by 2-1/4 inches overall under the head, you want the combined thickness of your clamped parts plus the nut and washers to finish inside that length, with a couple of threads past the nut. For stacked steel plate or a thicker bracket sandwich, move up to a longer length in the same G8HC and JG8HC Grade 8 series rather than relying on partial nut engagement.