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Robertson Screws...the Best Screws in the World?

Updated on January 9, 2018

Confused by the title?

Let me confuse you further with these two puzzles.

What are:-

Slotted, Crossed, Phillips, Pozidriv and Robertson?

Try this one: -

What are:-

Insulin, Telephone, Light Bulb, Five Pin Bowling, Wonderbra, Pacemaker …..and….. Robertson.

Let me put you out of your misery. The first puzzle is a list of the most popular screw drives. Yes, Robertson is a type of screw; a stunningly simple square-socket screw, invented and manufactured in Canada; a screw that can perform better than most screws.

The second puzzle is a list of the top Canadian inventions as voted by CBC’s viewers – the Robertson is number 7. This is quite a feat when you consider that the remainder of the list includes the Canadarm, the Zipper, Java programming, Standard Time, Instant Replay, the Electric Oven and Plexiglas. Yes, the humble, but subtle, screw is number 7.

I’m sure you have all used the slotted screw, the cross screw and the Phillips screw. You’ve probably also used the Pozidriv, mistakenly thinking it was a Phillips. Altogether, there are at least 27 different types of screw heads apart from the Robertson.

What makes the square-socket Robertson stand out from the rest, apart from its birthplace?

A sketch showing the taper in the Robertson screw..
A sketch showing the taper in the Robertson screw.. | Source

Advantages of the Robertson

Take your most basic single slot screw; hold its screwdriver in a vertical position and fit the screw onto the driver blade. It will just stay there without any help, but when you lower the screwdriver to a horizontal position, or below, the screw will fall off.

Now try the same thing with a cross headed screw; it will do better than the single slot, but it will still fall off before the screwdriver points straight down.

Try the same thing with the Robertson – the screw stays attached to the screwdriver with no problems whatsoever.

‘So what’ you shrug?

The ‘so what’ is this. As the Robertson is easily held in a horizontal position on the driver, it means that you don’t need two hands to drive the screw in. You can drive the screw in single-handed.

Now let me change your shrug into a gasp of amazement. With the Robertson you can do something that is impossible with the slot or the cross. You can hold the screw facing downwards without it falling off the driver.


The reason for this isn’t just because of the square socket; the recess in the screw head is tapered, as is the head of the screwdriver. This combination causes a wedge, making the screw head and driver head become a perfect fit.

The unique square recess in the Robertson screw head.
The unique square recess in the Robertson screw head. | Source

Peter L Robertson

For this extremely logical system of screwing and driving, we can thank Peter Lymburner Robertson. P.L. was born in Seneca Township, Ontario, in 1879, and died in 1951.

In the 72 years between those two dates, he managed to invent a screw and a screw driver, which are the established tools in Canada; build up a business that is still in existence today; write a book; annoy Henry Ford; help two war efforts, and what raises him higher in my estimation; supply the screws for the Mosquito fighter/bomber. Fabricated out of Canadian Spruce, the Mosquito was the 3rd sexiest plane in the skies during WWll.

Did you notice the three words in there that should resonate with you… ‘write a book?’ Fair enough, he did wait until he was 53 to write the book, The Remedy. In his book he formulated his theories of how to beat the recession. Whether the USA took heed of his book isn’t mentioned, but as he had to self-publish The Remedy, in 1932, and there was no such thing back then as the Internet or Amazon, it is extremely unlikely.

P.L. patented his screw and screwdriver at an earlier stage in his life, in 1909, when he was 30. The story goes that he was a screwdriver salesman, and when he was demonstrating a single slot screwdriver to a potential customer he cut himself with it. That would have been a bit of bummer. Most of us would have turned red with embarrassment, and either started selling something else, or made a remark like ‘THEY should do something about that.’

P.L. however, decided not to wait for ‘they’ but invented his own screw and driver. He not only patented the screw and the screwdriver, but also patented the machinery that he had invented to manufacture them.

The Robertson screw has been mostly confined to – and is standard - in Canada for over 100 years – apart from the fact that it is now being manufactured in Jiaxing, Zhejiang, China, that is. There are differing versions regarding the reason for the screws restriction to Canada. Some articles talk about how Robertson went into partnership with an English firm to make the screws under licence, and how he was treated badly when the firm declared bankruptcy - or - how the British government took the firm over. Whatever the reason, P.L. resigned as director in the British firm.

Again there are different versions of Mr Robertson’s clash with Henry Ford. Apparently Henry Ford liked the Robertson screws and he wanted to make the screws under licence, but after Robertson’s treatment by the English firm, he was hesitant of any such agreement, and refused. Henry then started using Phillips screws; invented by Henry F. Phillips in 1930. Another version says that the workers at the Ford plant didn’t want to use foreign materials, and that Robertson was unable to get his screws approved in the USA.

Tire Iron?

Not only did P.L. write a book himself, but after he died, a book was written about him by Edinburgh born Witold Rybczynski, ‘One Good Turn’ – an apt title, don’t you think?

Over the years, the Robertson square-socket screw has gained popularity around the world, but it has been a slow process. How slowly the word is spreading can be judged by my American daughter’s answer to a question. I had to send a box of items down south to my daughter who lives in Virginia. As I was phoning her to tell her the box had been sent, I had a thought.

“The box is screwed down with Robertson screws. Will you be able to open it without a Robertson screwdriver?”

“Opening it will be no problem, Dad. We have our own version of the Robertson screwdriver down here to open boxes; it’s called a Tire Iron, or as you would call it, a Tyre Lever.”

P.S. If you want to see Robertson's Head Office, go into Goggle maps and enter - Robertson Inc, Bronte Street North, Milton, Ontario.


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    • John MacNab profile image

      John MacNab 5 years ago from the banks of the St. Lawrence

      Hi mckbirdbks: I'm surprised that you've never heard of Robertson's before - mind you, after saying that I'd never heard of them until I came to Canada. It's an interesting story isn't it.

      The screws come in different sizes and need different screwdrivers. We have 4 different sizes of drivers here at home. Perhaps that's why they haven't caught on faster.

      Thanks for reading and commenting Mike.

    • John MacNab profile image

      John MacNab 5 years ago from the banks of the St. Lawrence

      Hi drbj: You know the old saying 'you learn something new everyday.' I'm glad you liked the hub, and thank you muchly for stopping to read it and comment on it.

    • mckbirdbks profile image

      mckbirdbks 5 years ago from Emerald Wells, Just off the crossroads,Texas

      Hello John, I have bought screw throughtout my career and never came across this Canadian opportunity. This is a remarkable article filled with new and enlightening information.

    • drbj profile image

      drbj and sherry 5 years ago from south Florida

      Can't believe I have existed all this time, John, without ever learning about the remarkable Robertson screw. Thanks for enlarging my sphere. Who knew?