Metallics CSF50F Anchors 1/4 X 3-1/4 Fh Ph Blu Conc Scr St-zn (Jar 100)

A 1/4 inch diameter concrete screw like the CSF50F installs into a 3/16 inch hole drilled with a carbide bit. No separate plug, shield or anchor body is needed, the screw cuts its own thread in the concrete. Drill the hole deeper than your intended embedment so cuttings have somewhere to go, and blow it clean before driving.

The CSF50F runs 3-1/4 inches overall. Concrete screws of this type want roughly 1 to 1-3/4 inches of embedment in the base material, so the usable grip above the surface is the remainder, which is why this length is the one people reach for when there is a sleeper, furring strip, sill plate or thick bracket between the fixture and the slab. For strut, straps and thin brackets going straight onto concrete, a shorter screw is the better choice.

Yes, if the hole is prepped for it. The CSF50F has a flat head with a Phillips drive, so it is made to be countersunk and finish flush rather than sit proud like a hex washer head. In wood or a metal bracket, countersink or use a factory-countersunk hole. Driving a flat head into a flat-faced bracket with no countersink leaves the head sticking up and can split or deform the part as it tries to seat.

The CSF50F is steel with a zinc coating, which is the standard blue concrete screw finish. That is fine for interior work and for protected exterior conditions, but zinc-plated steel is not the choice for constant wetness, coastal exposure or submerged conditions. For those, specify a stainless or heavier-coated concrete screw instead.

Concrete screws of this type drive into poured concrete, solid brick and the solid webs of concrete block. In hollow block, land the screw in the web, not the void, or the thread has nothing to bite. The CSF50F is a 1/4 inch diameter screw, so for hollow wall or void conditions you want a toggle or a sleeve-type anchor instead, not a masonry screw.

The CSF50F ships 100 screws to a jar, which is the pack type Metallics uses for this item. That quantity suits electrical rough-in work where you are setting strut, panel backing, conduit straps and box brackets to concrete across a job and want one container on the cart rather than loose boxes.

Order it as Metallics CSF50F. That covers the 1/4 inch by 3-1/4 inch flat head Phillips blue concrete screw in steel with zinc finish, packed 100 per jar. There is a single configuration under that number, so there is no diameter, length or finish option to specify separately.