Phillips Screwdriver Versus Robertson Screwdriver

The Phillips screwdriver and Robertson screwdriver were both designed in the early 1900's to overcome drawbacks associated with the slotted screwdriver. Each type of driver is used to drive screws that have recessed sockets in the screw heads but there are important differences between the two in terms of screw slippage and availability.

Phillips Screwdriver

The Phillips screwdriver was invented in Portland, Oregon in the late 1920s by Henry Phillips in an effort to faciliate the installation of screws using power screw drivers in an industrial setting. His design addressed several drawbacks to slotted screwdrivers, the most common type of screwdriver at that time.

The Phillips driver was purposely designed to cam-out or slip out of the screw to prevent over-tightening and breaking screws in assembly lines. (It was difficult to limit torque in early power screw drivers).

A Phillips driver is self-centering and is unlikely to slide out of the screw due to centrifugal force. Once the driver bit is inserted into the screw head recess, it will quickly seat itself as soon as the handle is turned.



Robertson Screwdriver

The Robertson square-head screw and screwdriver were invented in 1908 by Peter L. Robertson, a traveling salesman from Ontario, Canada. He sought a fastening system that would provide a firmer hold and less slippage than conventional slotted screws and screwdrivers.

Robertson’s design consists of a tapered square-tipped screwdriver that fits into a matching square recess (the "socket") in the screw head. This design makes a Robertson screwdriver less susceptible to cam-out than a Phillips driver because the driver bit inserts deeper into the screw head. Like a Phillips screwdriver, the Robertson driver is self-centering. This speeds up production and reduces product damage since slip-out rarely occurs.

Robertson screws and drivers are most commonly used in Canada due to Robertson's refusal to license his technology to other manufacturers. The more widely licensed Phillips head has gained greater acceptance worldwide, including the United States.

Screwdrivers In Use

A Phillips driver will sometimes require greater downward force on the screw than a Robertson driver to prevent the driver from slipping off the screw, especially for longer screws such as those used to attach cabinets to walls.

It is easier to use a Robertson screwdriver than a Phillips screwdriver one-handed because the tool tends to hold onto the screw, even if it is shaken. However, an annoying side effect of this "advantage" is that screw bits can sometimes get stuck in the screw head.

It is more difficult to remove a painted-over or rusted Philips head screw than a Robertson head screw because the Robertson screw provides more depth for the driver to "bite" into.

Tip Sizes

There are seven different Phillips drive sizes, designated 000, 00, 0, 1, 2, 3, and 4 (increasing in size). Sizes 0-4 are most commonly encountered.

Robertson screwdrivers are available in five different tip sizes, with the size indicated by a distinctive color. From smallest to largest, these are: orange (#00), yelllow (#0), green (#1), red (#2), and black (#3).

The compactness of the Robertson head works well for trim head screws and other compact head screws. The Phillips design does not lend itself as well to such screws.