Metallics CSF40SS Screws 1/4 x 2-3/4 FH PH Conc Scr Anc (100pcs)

A 1/4 inch concrete screw anchor is set in a 3/16 inch carbide hammer-drill hole. Drill the hole deeper than the intended embedment so the dust has somewhere to go, blow it out, then drive the screw. At 2-3/4 inches of length you have room for a thicker fixture or standoff and still get useful embedment into the base material.

No shield, sleeve, or plug is needed. A concrete screw anchor cuts its own thread in a drilled hole in concrete, block, or brick and is driven straight in with a screw gun, which is why electricians use them in place of two-piece sleeve or drop-in anchors for light and medium duty mounting. It also backs out again, so a strap or box can be repositioned.

The CSF40SS has a flat head, so it countersinks flush where the fixture has a chamfered or countersunk hole, and sits nearly flush on flat sheet metal. That matters where a cover plate, trim ring, or panel has to go back over the fastener. If you need bearing area on an unchamfered strap or washer, a hex washer head concrete screw is the better choice for that detail.

Concrete screw anchors are for solid base material, poured concrete, solid block, and brick. In a hollow block web or in drywall alone the thread has nothing to cut into and the anchor will spin out. For hollow wall work use a toggle or a self-drilling drywall anchor instead, and reserve the CSF40SS for the solid sections.

Metallics catalogues the CSF40SS as electrical fastener stock, and it is the anchor electricians reach for when fastening strut, device and junction boxes, conduit straps, and hangers to concrete ceilings and walls. There is nothing electrical-specific about the fastener itself, so it works equally for general mechanical and MRO anchoring in the same base materials.