10/07/2026
🔩 He said no to Henry Ford, and that's why Canada still uses a different screw
In the early 1900s, a young Ontario salesman named Peter L. Robertson was demonstrating a spring-loaded screwdriver when the blade slipped out of a slotted screw and sliced his hand open.
Most people would have just bandaged it up. Robertson decided to fix the problem.
He developed a screw with a square socket in the head and figured out how to mass-produce it, which was the hard part. He opened his own factory in Milton, Ontario, in 1908 and patented the design in Canada in 1909.
Why was it better?
✅ The square socket grips the bit, so it's far less likely to slip
✅ It can handle more turning force before stripping
✅ The slightly tapered hole holds the screw on the bit, so you can drive it with one hand
Factories noticed. Ford's Canadian operations used Robertson screws in car bodies and found they sped up assembly.
Then Henry Ford wanted a deal on his own terms, with control over the supply.
Robertson said no.
Years earlier, he had lost control of a business venture in England, and he wasn't going to let it happen again. He kept tight control of his invention, even if it meant walking away from the most powerful carmaker in the world.
The result? The Robertson screw never took over the world. When the Phillips screw arrived in the 1930s, the American auto industry adopted it, starting with General Motors, and much of the world followed.
But in Canada, Robertson's square screw stuck.
More than a century later, it's still a staple of Canadian construction, woodworking and home toolboxes. Ask any Canadian tradesperson which screw they'd rather drive and you'll probably get a strong opinion.
P.L. Robertson died in 1951, but his little square hole is still one of the most Canadian things in your house. 🍁
