Metallics G8HC34712 Bolts 3/4-10 x 7-1/2 G8 HXBT St-zn (Box 25)

It's a 3/4-10 bolt: 3/4 inch diameter with 10 threads per inch, which is standard UNC coarse thread. Any 3/4-10 UNC nut or tapped hole will take it. Measured shank diameter runs 0.7410 to 0.7500 inch. Pair it with a Grade 8 nut so the nut isn't the weak point in the joint.

The Metallics G8HC34712 is Grade 8, rated at 150,000 psi minimum tensile and 130,000 psi minimum yield, with a hardness of Rockwell C33-39. Grade 5 tops out lower, which is the whole reason this bolt exists: use it where the joint load exceeds what a Grade 5 can carry, as in automotive and fleet work. It's medium carbon steel, heat treated, per AISI 1021-1045.

Head width across flats measures 1.100 to 1.125 inches, so a 1-1/8 inch socket or wrench is the fit. Across corners it runs 1.240 to 1.299 inches, which is what you need to clear if you're driving it in a counterbore or a tight bracket pocket.

It's zinc plated steel. Zinc gives mild corrosion protection, fine for indoor, enclosed, or sheltered equipment mounting. For sustained outdoor exposure, salt, or wash-down duty, zinc plating will eventually give up; a hot dip galvanized or stainless fastener is the better call there, though neither will match Grade 8 strength in stainless.

These ship as a 25 count box, and 25 is the order minimum, so the box is the smallest unit. The full box weighs 25.54 lbs. Metallics does offer other sizes and quantities of the G8HC series by request.

The Metallics G8HC34712 is flagged Buy American compliant and ARRA compliant in the manufacturer's data, with country of origin listed as China. On federally funded work, hand both facts to your compliance reviewer, since the governing clause on your contract decides which one controls.

It's a 3/4-10 by 7-1/2 inch bolt. At that length a Grade 8 hex cap screw is run with a partial thread and a plain shank under the head, so you get a grip section through the joint rather than threads bearing in the hole. If you need thread engagement the whole way, a fully threaded tap bolt is the part to ask for instead.

Head height runs 0.455 to 0.483 inch, so budget just under half an inch of stack above the joint face. That matters if the bolt head sits under a cover plate, a shroud, or a moving component.