Types of Screws
Screws come in a wide variety of shapes, sizes, and materials. Choosing the correct fastener for a particular application requires careful consideration of factors such as head type, threading, diameter, material, coating and finishing treatment. This article will introduce you to some of the most common head types and their typical applications:
Socket Set Screws The socket set screw, or socket cap screw, exerts compressional or clamping force against the object it is tightening, rather than the tensile (or elongating) load created by bolts or most other screws. It also has a smaller head than other screw drive types, and the head is recessed into a countersunk hole, leaving no protruding parts that might catch on objects or surfaces in use.
Flat Head (82 degrees) – Standard countersunk style, generally used for light-duty applications such as wood decking or drywall. Also known as a bugle head.
Oval Head – A decorative dome-shaped heads, commonly used for switch coverings. Oval heads have a similar angle to flat heads but require less countersinking.
Fillister Head – A slightly rounded top with tall cylindrical sides, fillister heads provide a larger bearing surface in low-clearance applications and can be successfully substituted for other round styles.
Modified Truss Head / K-Lug – Provides additional large bearing surface in low-clearance applications, with a lower profile than pan heads. Also provides more space for wire connections than flat or oval heads.
Torx – A six-sided hex-shaped head that fits into a hexagonal drive hole, allowing for greater torque than a standard slotted or Phillips drive. This design is also more secure against tampering, and it's often used in high-security applications, such as correctional facilities.Button Head Screw