Metallics JBLS31 Bolts 1/2 x 3-1/2 Hx Lag Blt St-zn (Jar 50 )

No. The JBLS31 is a zinc plated steel lag bolt specified for use in wood in non-corrosive environments. Zinc plating is a mild indoor/dry-location coating, so for exterior exposure, pressure treated lumber, or any corrosive setting you want hot dip galvanized or 18-8 stainless lags instead.

Size the pilot to the shank, not the thread. The JBLS31's body measures 0.482 to 0.515 inch outside diameter with 6 threads per inch, so the lead hole in solid wood is drilled to roughly the root diameter of the thread and the clearance hole in the member being fastened is drilled at full 1/2 inch. The gimlet point helps it start, but at 1/2 inch diameter it still has to be driven with a wrench or impact on a hex socket, not hand-started.

The JBLS31 is made from AISI 1006-1022 low carbon steel with a 60,000 psi minimum tensile strength and a Rockwell B70-B100 hardness. That is standard commercial lag screw material, suitable for general wood anchoring of strut, hangers, brackets and equipment. It is not a heat treated high strength bolt, so if a drawing calls for a specific structural grade, match the grade on the drawing.

No. The JBLS31 lag bolt is not Buy American compliant and is not ARRA compliant, with multiple countries of origin. On a federally funded project with domestic sourcing requirements, this part will not satisfy the spec.

The hex head measures 0.725 to 0.750 inch across the flats, which is a 3/4 inch wrench or socket. It is a standard hex head lag made to ASME B18.2.1-1996 dimensions, so a 3/4 inch impact socket seats on it without issue.

It is a full bodied lag with spaced threads and a gimlet point rather than a fully threaded rod, so there is an unthreaded shank below the head. On a 3-1/2 inch lag that means you lose some embedment to the shank plus whatever thickness of material you are fastening through, so plan on the thread engaging the last couple of inches in the receiving member. If you need deeper bite in a thick assembly, step up to a longer length.

The JBLS31 ships as a jar of 50 pieces, and 50 each is the order minimum, so the jar is the smallest buy. Metallics notes other sizes and quantities in the BLS and JBLS lag bolt line are available by request if 1/2 x 3-1/2 is not the length you need.

That is exactly the application. Metallics lists the JBLS31 for the electrical, plumbing, heating and air conditioning trades, anchoring into wood. A 1/2 x 3-1/2 hex lag is the common size for fastening strut channel, beam clamps, trapeze hangers and equipment brackets to joists and blocking. Pair it with a flat washer under the head to keep the hex from pulling into soft wood.

The JBLS31 is specified for wood, not for direct installation in masonry. Lags of this type are commonly driven into lead or plastic lag shields set in concrete or block, but the thread is cut for wood, so for a direct concrete anchor use a wedge anchor or a screw anchor rated for concrete instead.

Right hand thread, so clockwise drives and tightens with any standard driver, ratchet or impact gun. No reverse thread surprises on this one.