Screws and bolts are designed with a recess so that they can be driven into and out of workpieces. Found on the head, it consists of an indention in a specific shape. There are many different types of drive recesses for fasteners, some of which include the following.
Square
Also known as a Robertson drive, a square drive recess lives up to its namesake by featuring the shape of a square. It allows for the delivery of more torque than that of other drive recesses while also preventing slippage of the bit. Fasteners with a square drive recess are commonly used in drywall, furniture and other woodworking applications.
Slot
A slot drive recess is characterized by a single indentation that runs horizontally across the top of the fastener’s head. It supports the use of a flat-bladed bit. Fasteners with a slot drive recess don’t offer as much torque as those with a square drive recess, so they are used in simple woodworking applications that require less twisting force.
Cross
There are also fasteners with a cross drive recess. A cross drive recess is similar to a slot drive recess, except it has two indentions: one indention runs horizontally across the top of the fastener’s head, whereas the other runs vertically. Fasteners with a cross drive recess offer redundancy. If one of the slots is deformed, the fastener can still be removed by gripping the other slot with a bit.
Phillips
One of the most common drive recesses is Phillips. It was invented by John P. Thompson, who later sold the design to Phillips Screw Company founder Henry F. Phillips. A Phillips drive recess consists of a plus sign (+) with webbing around the center. With its ability to cam out, it’s used in a diverse range of applications, including woodworking and manufacturing.
Fearson
Another common drive recess is Fearson. Many people assume that Fearson is just another name for Phillips. While they look similar, though, they are two unique drive recesses. A Fearson drive recess consists of a smaller plus sign (+) than its Phillips counterpart. Additionally, it doesn’t have webbing around the center. Fasteners with a Fearson drive recess are commonly used in marine applications because they can be installed and removed using a single bit.
Torx
While not as common as the aforementioned drive recesses, some fasteners use a Torx drive recess. This alternative drive recess features the shape of a six-point star. With six individual lines, it allows for a superior level of torque than most other drive recesses. Fasteners with a Torx drive recess are practically immune to slippage and cam out, making them an excellent choice for automotive and electrics applications.
These are just a few of the most common drive recesses. There are also hex drives, such as hex socket and double hex, that require the use of a hex wrench to install or remove. A hex socket features a hexagonal shape, whereas a double hex socket features two hexagons.