Metallics JHW38312 Anchors 3/8 X 3-1/2 Hmmr Drv Wedge Zn-C (Jar 50)

Drill a 3/8 inch hole. Wedge anchors use a hole the same nominal diameter as the anchor, so a 3/8 inch carbide bit matches the JHW38312. Drill deeper than the embedment you need so dust at the bottom of the hole doesn't stop the anchor short, blow or vacuum the hole clean, then drive the anchor until the nut and washer seat and torque it to expand the clip.

Zinc plated carbon steel, which is what the JHW38312 is, is intended for dry interior concrete. Plating gives some corrosion resistance but it isn't a marine or permanently wet-location finish. For exterior slabs, parking structures, pool decks, or wash-down areas, use a stainless steel wedge anchor instead.

Wedge anchors like the 3/8 x 3-1/2 JHW38312 are for solid poured concrete. The clip expands against the wall of the hole, which needs dense solid base material to react against. In hollow block, brick, or grouted CMU the hole wall can blow out or the anchor can spin, so use a sleeve anchor, a screw anchor rated for masonry, or an adhesive anchor with a screen tube in those substrates.

Each jar holds 50 of the 3/8 x 3-1/2 zinc plated wedge anchors, packed in a jar rather than a loose box, which keeps them sorted on a cart or in a gang box. Nut and washer are part of the assembly on a wedge anchor, so you are not buying those separately.

A hammer drive wedge anchor, the JHW38312 style, goes into the drilled hole as one piece and is set by hammering it down and then torquing the nut, which pulls the cone into the expansion clip. It is a through-fixture anchor, so you drill through the item you are mounting and the hole in the concrete in one pass. A drop-in anchor is set flush first and takes a threaded bolt afterward, which is what you want when the fixture has to be removable or when you are hanging threaded rod from a deck. For a bolted-down, permanent attachment, the wedge anchor is the simpler choice.

No. Once the 3/8 x 3-1/2 wedge anchor is driven and torqued, the expansion clip is permanently set in the hole. You can back the nut off and take the fixture away, but the anchor body stays. To clear the surface, cut or grind the stud flush, or drive it below the surface and patch. Plan on fresh anchors for any relocation.

The Metallics JHW38312 is an electrical-department anchor, and 3/8 x 3-1/2 is the common size for securing strut channel, trapeze supports, panel and enclosure backs, transformer and generator bases, and conduit clamp feet to concrete floors and walls. Pipe fitters and mechanical trades use the same size for equipment bases and pipe supports.

Keep 3/8 inch wedge anchors back from the edge and apart from each other, because expansion anchors push outward on the concrete and a shallow edge distance cracks the slab and drops the holding value. Standard practice is to hold edge distance and anchor spacing at several anchor diameters, so a few inches for a 3/8 inch anchor, and to move the layout rather than set one right at a slab edge or a control joint.