Masonry screws are a self-tapping screw that can be used in a variety of base materials that include: concrete, brick, mortar joints/block and CMU. They are manufactured out of stainless or carbon steel and come with or without a corrosion coating. Masonry screws are available in two different head styles, each designed for different applications. For applications where the head needs to be countersunk in the material, a flat countersunk Phillips head screw should be used. If the screw head will be on top of the material then a hex washer head should be used.
Concrete screws have alternating high and low threads. The lead thread on the masonry screw does all the cutting of the masonry material while the screw is being installed. The lead thread will dull and hit a point where it will no longer be able to cut threads and will stop screw penetration. The abrasiveness of the masonry material will determine the exact length any specific screw can tap.
When installing masonry screws a pilot hole must be drilled with a carbide drill bit before inserting the screw. The diameter of the pilot hole is critical and must be drilled in accordance with the manufacturer’s instructions. The size of the pilot hole must be correct or it could cause the screw to break on insertion, will strip the hole, or will not provide the rated holding force.
Pre-drilling is recommended especially when using hardwoods
Tapered, partially threaded shank, shorter lengths are fully threaded
Sharp gimlet point for easy startup
Coarse and sharply crested threads, creates its own internal mating threads
Creates a tight joint, but can be removed easily without damage
Wood screws have a sharp gimlet point and a tapered partially threaded shaft, shorter lengths are fully threaded. Wood screws are commonly available with flat, pan, or oval heads. The unthreaded portion of the shank is designed to slip through the top board and prevent cross-threading as it pulls the two pieces of wood together.
Wood screws have coarse, sharply crested threads that create their own internal mating threads. Thread styles can greatly differ, especially in-depth and spacing. Coarse (large) threads are made for use in softwoods. While fine (smaller, closely spaced) threads work best in hardwoods. Extra coarse threads are designed for use in particleboard. High-low threads are typically found on general-purpose screws and work well with most types of wood. Serrated threads have “teeth” that help cut into the wood and make it easier to drive.
- Drywall screws may be used to fasten drywall to both wood and metal studs
Drywall screws feature a bugle shaped Phillips head
The diameter of drywall screw threads is larger than the shaft diameter
A versatile construction fastener with many uses
Drywall screws have a bugle shaped Phillips head and a sharp piercing tip designed to attach drywall to wood and metal studs, while not damaging the drywall in the process. When finished driving, drywall screws are recessed slightly into the drywall. Drywall screws are typically manufactured out of case hardened steel with a black phosphate finish.
Drywall screws with coarse threads are used to attach drywall to wood framing. While drywall screws with a fine thread are best suited for attaching drywall to light-gauge steel framing. Self-drilling drywall screws are also used when working with metal studs or frames.