Robertson Screwdriver: The Square Drive Guide

The Robertson screwdriver uses a square-tapered recess that self-centres on the screw, resists cam-out, and can be driven one-handed. Invented by P.L. Robertson in Milton, Ontario in 1908, it is the dominant screw drive in Canadian construction - and virtually unknown elsewhere.

Why Robertson Didn't Go Global

P.L. Robertson refused to license his design. When Henry Ford wanted to use Robertson screws on the Model A assembly line in the late 1920s, Robertson insisted on manufacturing the screws himself rather than granting Ford a license. Ford walked away and later adopted the Phillips drive instead. That single decision shaped global screw standards for the next century.

Robertson Sizes and Color Codes

Why Tradespeople Prefer Robertson

• Self-centering - the tapered square seats in the screw and holds without a magnet
• No cam-out - the square recess transfers torque directly with no tendency to slip
• One-handed driving - the screw stays on the driver tip, freeing the other hand
• Faster than Phillips - no need to press hard to prevent cam-out
• Works well with power tools - positive engagement means fewer stripped screws

In Canada, Robertson is the default for wood screws, decking, drywall (sometimes), and most construction. The square combo drive - a screw head that accepts both Robertson and Phillips - has helped Robertson gain some traction in the US market.