Metallics HTB33M Bolts 1/2-13 X 2 Hx Tap Blt St-zn (Box 1000)

The HTB33M is a 1/2-13 hex tap bolt, 2 inches long. The 13 is threads per inch, which is standard UNC coarse thread for a 1/2 inch diameter, so it mates with 1/2-13 nuts, strut channel nuts, and tapped 1/2-13 holes. Threads run the full length, which is what separates a tap bolt from a partially threaded hex cap screw.

The HTB33M is steel with a zinc finish, which suits dry interior and sheltered work, light outdoor exposure, and general electrical support steel. Zinc plating is a sacrificial coating, not stainless, so for roof-mounted gear, coastal sites, wash-down areas, or buried work step up to 18-8 stainless or hot dip galvanized hardware instead.

Tensile strength is 60,000 psi minimum with hardness of Rockwell B69 to B100, which is low carbon commercial grade, equivalent in strength class to a Grade 2 fastener. That is fine for strut and channel, conduit racks, enclosure and equipment mounting, and general non-structural anchoring. For structural steel connections or anywhere the drawing calls out a higher grade, use Grade 5 or Grade 8 hardware instead.

Yes. The bolt is 1/2-13 UNC, which is the thread used on standard 1/2 inch channel nuts and spring nuts, so it threads straight into them for conduit racks, trapeze hangers, and equipment supports. Head is a plain hex at 3/4 inch across flats, driven with a standard socket.

Head width across flats measures 0.725 to 0.750 inches, so a 3/4 inch wrench or socket is the fit. Across corners the head runs 0.826 to 0.866 inches, worth knowing if you are driving it in a tight channel or next to a flange.

Metallics lists the HTB33M as compliant for both Buy American and ARRA. Country of origin is China, so if your contract requires domestic melt and manufacture rather than the ARRA/Buy American classification the manufacturer assigns, confirm which standard the spec actually cites before you submit it.

The HTB33M ships as a box of 1000 and the order minimum is 1000 pieces, so it is a bulk buy rather than a count-out item. Metallics does make other sizes and quantities available by request if 1000 of this size is more than the job needs.

A hex tap bolt is threaded the entire length under the head; a hex cap screw has a plain unthreaded shank below the head. Full thread, as on the HTB33M in 1/2-13 x 2, is what you want when you are threading into a tapped hole, a strut channel nut, or clamping a stack where you need thread engagement right up to the head. Pick a cap screw instead when the joint needs a smooth shank bearing in a reamed hole.

A full box of 1000 of the 1/2-13 x 2 bolts weighs 132.4 lbs and the carton measures 9 x 9 x 6.13 inches. That is a two-hand lift, so plan the delivery drop point and don't expect it up a ladder in one trip.

Thread conforms to IFI-199 (2014). That matters when a submittal or inspector asks for a thread standard callout, and it means the 1/2-13 threads interchange with other hardware built to the same industry fastener standard.