The Round Washer Head design, which can also be known as wafer head screws, K-Lathe screws and modified truss screws, could quite possibly be the most multipurpose head design offered. It combines the benefits of the Pan Head design but has an attached washer built on to the head to increase head diameter. This helps prevent over-driving in softwoods. General cabinet assembly, installation, hinges, metal drawer slides, wooden drawer guides, attaching lights and brackets are just a few applications where the Round Washer Head design is used. The addition of the washer provides maximum bearing surface to allow for "over-driving" the screw to tighten those stubborn joints easily. These Fasteners are also self tapping screws in that they tap their own mating threads and do not need pre threaded inserts like machine screws. It was originally designed for the construction industry to attach wood lathe and metal framing to 20 to 25 gauge steel studs They were desired because they were low profile and drywall could be laid on top of them. They also can be known as ply-metal because they can be used to attach plywood to metal. The big wafer head sinks into the plywood and has a large bearing surface. The length is measured from underneath the head to the tip of the screw.

They are available in Philips drive as well as square drive, which is At times referred to as Robertson drive. They are available in stainless steel and well as standard carbon steel and with plain or painted heads. They are available in sharp points as well as self drilling points. When asking for these parts from your hardware store or wholesale fastener distributor, you should also make sure to specify whether you need these zinc plated or black oxide to prevent getting the wrong part.

These are also known as:

Round Washer Head Needlepoint (zip screws) or Self-drilling (Tek Type) Screws

Wafer Head Needlepoint (zip screws) or Self-drilling (Tek Type) Screws

K-Lathe Screws

Modified Truss Needlepoint (zip type) or Self-Drilling (Tek Type) Screws

Sharp point - zip screws - or self drilling - tek type - screws, these screws are also self-tapping screws as they tap their own threads in to the materials they are used with and do not need to be used with a pre-threaded mate such as a nut or insert.