By Dr. Jody Muelaner
Pan head screws take their name from the appearance of their head, which looks similar to an upside-down frying pan. Pan head screws are a common head type of non-countersunk screw head used in wood screws, self-tapping screws, self-drilling screws, and machine screws.
They have wide heads, a flat bearing surface, high vertical, chamfered, or curved sides, and a flat or slightly domed top surface with a recessed socket. The socket is typically a slot, particularly for wood and self-tapping screws. Hexagon sockets are also common for machine screws.
Pan head screws are used in a wide range of applications, including:
- Where a flat bearing surface is required
- There’s a risk of the head being caught in use
- A decorative fixing is desired.
The large diameter of pan head screws, combined with high edges, provides a large, deep socket. This enables high torque during assembly while minimizing cam-out which could result in damage to the screw. The flat underside of a pan head screw provides a large mating surface area, which allows a firm hold, even with enlarged holes, and minimizes crushing.
The flat or slightly domed profile provides a trim finish for decorative applications and minimizes the risk of catching the screw head while in use. Pan head screws employ a variety of socket types or drive designs, including slotted, Phillips, hexagon socket, Pozidriv, Torx, and square drive. They may be zinc-plated, white-coated, black-coated and non-coated stainless steel.
Pan head machine screws are typically used where a hex head might catch or would appear out of place, but where the material is not thick enough to support a counterbored or countersunk hole. Pan heads with slotted sockets are also better suited to light applications and can be fastened more conveniently using a screwdriver.
Pan head wood screws are used to fasten flat materials to timber.
Pan heads are similar to round heads, truss heads, and binding heads, although pan heads have largely replaced these other heads in modern screws. Round-head screws have a domed head and a small bearing surface, applications using round heads demand a high level of aesthetics. Truss head screws have an extra-wide head and a low profile, applications using truss head screws require coverage for large holes or extra-low clearance.
Binding head screws have an extra deep head and socket, applications using binding head screws require extra high tightening torque.