Saturday, August 29, 2009

Peter Lymburner Robertson's Screwdriver

I had occasion to be working on a project around the house and I came across some screws that needed to be removed from a retractable screen.  Much to my amazement, none of my screwdriver bits would work. It looked like an Allen head, but not hex. 

I went to the local hardware store that carries everything and found out that was a square headed screw.  Further, since the square hole is tapered, it allows for a very secure grip -- one that will not slip and strip the screw head.  Interesting!  I needed to investigate this. Is this a new screw head?

The Robertson appellation was given to me by Canadian Russ McKinnon.  The Internet is amazing. With this information I was able to locate an excellent article by Susanna McLeod about Peter Lymberner Robertson and his Screwdriver. It is so good, in fact, that I include it here in its entirety with permission from the author.

The Invention of the Square-Head Screw and Driver

© Susanna McLeod

From Canadian History @

A mishap led to the invention of the Robertson screw and screwdriver, patented in 1909. The design remains popular: 85% of screws sold in Canada are Robertson's.

There are several versions of the story: Whether he was demonstrating a spring-loaded screwdriver, as mentioned in Mysteries of Canada, or setting up a booth to sell tools, as noted by Canadian Home Workshop, the fact is that Peter Lymburner Robertson cut his hand while he used a regular slot-head screw and screwdriver. The injury was enough to encourage the man to come up with a new device, something that would have a firmer hold and less slippage.

In 1909, Robertson received Canadian patents for his invention of a square-head screw and driver. The design permitted driving “a screw more quickly…,“ said Cool Canada, “and the screw was self-centering so only one hand was needed.” The screwdriver fit better in the head of the screw, so there was less opportunity of sliding out, and less chance of injury.

Competition for Robertson

The competition did not care for Robertson’s invention. The Steel Company of Canada tried to have his patents quashed and “a scathing story about him appeared in a 1910 issue of Saturday Night magazine,” according to the book, I Know That Name! , by Mark Kearney and Randy Ray. Robertson sent his own letter to the editor, and the attempts to overthrow his gains were unsuccessful.

The Robertson screw and screwdriver were hugely popular, seen by manufacturers as a way to speed up production and lessen product damage. Mysteries of Canada mentioned that “The Fisher Body Company, which made wooden bodies in Canada for Ford cars, used four to six gross of Robertson screws in the bodywork of the Model T and eventually Robertson produced socket screws for metal for the metal bodied Model A.” Henry Ford so appreciated the new screw that he wanted a licencing arrangement for control of the time-saving tools. Peter Robertson refused to give up control.

500 People Employed

With his company, Recess Screws Limited, founded in England, Robertson opened a manufacturing facility in Milton, Ontario. At the end of World War II, he employed 500 people in the production of three colour-coded sizes of the Robertson – green for small, red for medium and black for large. (There is now yellow, for very small drivers.) Still remarkably popular, the square-head screw controls 85% of the market in Canada, said Canadian Home Workshop. The Americans are less familiar with the design, but the Robertson's still own 10% of the American market.

Born in 1879, Peter Robertson went from salesman to millionaire with his invention.  A good design that is tough to top, there has been nothing to improve on the Robertson screw since.  Robertson made good use of his fortune, becoming a renowned philanthropist. He died in 1951.


I Know That Name!: The People Behind Canada's Best-Known Brand Names, by Mar Kearney and Randy Ray, published by Dundurn Press 2002. pp 24.

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