Metallics JHTB27 Bolts 3/8-16 X 3-1/2 Hx Tap Blt St-zn (Jar 50)

The JHTB27 is a 3/8-16 x 3-1/2 inch hex tap bolt, so 3/8 inch diameter with 16 threads per inch (coarse UNC) and a 3-1/2 inch length. Thread form is made to IFI-199 (2014). Being a tap bolt, it is threaded the full length rather than having a plain shank, which is what you want when you are threading into a tapped hole, a channel nut, or a strut insert instead of through a stack of material.

Rated at 60,000 psi minimum tensile with a hardness of Rockwell B69 to B100. That is general-purpose low-carbon steel fastener territory, fine for strut, conduit supports, hangers, equipment mounting and similar MRO work. If a drawing calls out a specific SAE grade with a higher tensile, such as a Grade 5 or Grade 8 bolt, this is not a substitute for it.

The JHTB27 is steel with a zinc finish, which handles indoor and normally dry or occasionally damp locations well. For sustained exterior exposure, washdown areas, coastal sites, or anywhere corrosive, go to the stainless version of the same hex tap bolt (18-8 stainless) rather than zinc plated steel. Zinc plating is a sacrificial coating and will eventually give up in a wet environment.

The JHTB27 ships as a jar of 50 bolts, and 50 each is the order minimum, so the jar is the smallest unit sold. Other sizes and quantities of the hex tap bolt are available by request if a job needs a different length or count.

It is a hex head measuring 0.544 to 0.562 inch across the flats, which is the standard 9/16 inch wrench or socket size for a 3/8 inch bolt. Handy to know before you send a crew up a lift with the wrong tool roll.

The JHTB27 hex tap bolt is flagged compliant for both Buy American and ARRA on its product record, which is what institutional, government and public-works procurement typically needs documented. Country of origin is listed as multiple, so if your spec requires a single named origin on the submittal, ask for origin confirmation on the lot you are buying.

They look alike but are threaded differently. A tap bolt like the JHTB27 is threaded the full 3-1/2 inches, so it keeps biting no matter how deep it goes, which suits threading into tapped holes, channel nuts and inserts, or clamping thin assemblies where you want thread right up under the head. A hex cap screw has a plain unthreaded shank under the head and is the better pick when you are passing through a clearance hole and want the shank bearing on the hole rather than threads. For strut and conduit support work in the trades, full-thread tap bolts are the usual call.