The venerable flat head screw has been the woodworker’s friend since the early 1700s. But it’s been eclipsed by more modern drivers like Phillips head screws and hex sockets. But even with the historical avalanche of screw and driver types, there is still a place for the simple flathead screw in most toolboxes.
The flathead screw is a workhorse, and has been used to put together all sorts of things including cabinets, bookcases, stair threads, tables and benches. It can also be used for general construction tasks such as hanging drywall and mounting doors.
But the flathead screw isn’t without its drawbacks. A screwdriver that’s too big for the screw head can easily damage it. A screwdriver that’s too small can be difficult to turn, especially if you apply a lot of force.
There are several types of flathead screw heads, each designed for specific applications. For example, the Modified Truss Head / K Lath head provides an extra large bearing surface. The Oval Head / K -Lath head includes a decorative rounded finish that is often used for switch coverings. The Oval Undercut Head / Rounded Washer Style is used in some shorter screw lengths to provide longer thread grip and deeper countersinking.
Before you drive or loosen a flathead screw, make sure that the screwdriver’s blade fits snugly into the slot on the fastener head and doesn’t have any wiggle room. It’s also important that you use the right screwdriver size for the job at hand–don’t use a slotted screwdriver for Phillips or combination screws or a hex key for Torx screwdrivers. Flat Head Screw