Metallics CSF4SS Anchors 3/16 X 2-3/4 Fh Ph Conc Scr SS (Jar 100)

A 3/16 inch concrete screw is driven into a 5/32 inch hole drilled with a carbide bit, and the hole should go deeper than the embedment so dust has somewhere to go. With a 2-3/4 inch screw, subtract the thickness of whatever you are fastening to get your embedment, then drill at least a half inch past that. Blow or vacuum the hole clean before driving, or the screw will bind short of seating.

Stainless steel is the reason to pick the CSF4SS over a plated carbon steel concrete screw. It holds up in wet and exterior work, parking structures, coastal sites and wash-down areas where a zinc-plated screw rusts at the head and stains the concrete. It is also the right choice when you are fastening a stainless or aluminum bracket and want to avoid a dissimilar-metal problem at the fastener.

Concrete screws of this type bite into poured concrete, grout-filled or solid CMU block, and brick. They are not for hollow drywall, hollow block webs or wood framing. For electrical work that means strut, conduit clamps, box brackets, panel backs and device plates fastened to a hard masonry wall. In hollow block, land the screw in the solid web or use a hollow-wall anchor instead.

No plug, sleeve or shield is needed. The CSF4SS is a one-piece concrete screw, so it cuts its own thread in a clean 5/32 inch drilled hole and can be removed and reinstalled. That is the practical difference from a drop-in or sleeve anchor, which needs setting and cannot be backed out. All you need on site is a carbide bit and a Phillips driver.

Only if the fixture hole is countersunk or chamfered. A flat head seats by wedging into a tapered seat, so against a flat, unchamfered hole in sheet metal it can deform the hole or stand slightly proud rather than clamping evenly. For plain punched holes in strut, clamps or box brackets, a hex washer head or pan head concrete screw spreads the load better. Use the CSF4SS where flush is the requirement.

The CSF4SS ships 100 screws per jar. That is a shop or van quantity for a stainless concrete screw, so one container generally covers a strut run or a batch of box and bracket mounts without reordering mid-job. The jar also keeps the heads from getting chewed up loose in a bucket.