Peter Lymburner Robertson's Screwdriver

The Invention of the Square-Head Screw and Driver

Jun 26, 2008 Susanna McLeod

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 Robertsons.

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 Robertsons 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.

Source:

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

The copyright of the article Peter Lymburner Robertson's Screwdriver in Canadian History is owned by Susanna McLeod. Permission to republish Peter Lymburner Robertson's Screwdriver in print or online must be granted by the author in writing.

P.L. Robertson	Patent Page for Robertson Screw, 1909	P.L. Robertson
Promotional Card for the Robertson Screw, 1909

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Oct 28, 2008 9:03 PM

Guest :

I would hate to be the one responsible for the possible dethroning of Canadian P.L. Robertson as the inventor of the square recess used to drive wood screws, but I have stumbled across a patent in the USPTO for the exact same design, but 34 years earlier.
The United States Patent Office has Patent Nbr. RE006729 issued to one Allan Cummings of New York City, and assigned to The New York Screw Co,
with an reissue date of November 9, 1875.
Anyone care To comment ?
Regards
AJ

Oct 20, 2009 7:12 PM

Guest :

Hey AJ,

Fear not, you are not de-throning anyone. The US patent you are referring to (A. Cummings' US patent 6,729) is not the same as the Robertson patent. This is a common misconception, so don't feel bad. If you take a close look at Cummings' patent, the sides of the screw socket are parallel to each other. This was the Achilles Heal of his design; it leads to binding of the screwdriver when inserted and/or removed from the socket unless it is inserted almost exactly parallel to the sides of the socket. Robertson significantly improved on this design by tapering in the sides of the screw socket from top-to-bottom, thereby allowing a greater range of freedom of the screwdriver as it is inserted and removed from the screw without binding. Significant improvements on a patent, such as this one was, and currently is, justifiably patentable. This is what Robertson did.

Henry Ford saw the value of the Robertson screw in mass production, but because he could not purchase some/all of the rights to this technology, he abandoned it (sour grapes IMHO). (Note that he did not pursue the Cummings patent -- no surprise!) It has been America's loss to date as it is a far superior screw head to either the slot or the Phillips head, both of which cam-out far too easily.

RB

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