Thursday, February 02, 2006

The Robertson screw

The Ground Zero Games mailing list recently had a post from someone in Australia explaining how some young players didn't know how many inches there were in a foot, as Australia was metric. This resulted in me posting about Canada's use of the metric system except in the building trades. (Most carpenters and trades people refused to go metric when Canada went metric, and the building supply companies prefer to deal in imperial measure so as to be compatible with the U.S.) In the post I happened to mention one of the best Canadian inventions ever: the Robertson screw. This elicited enough interest by American members of the list that I thought I'd mention it in Designated Import.

The Robertson screw is a screw with a square slot in it, instead of the X shaped notch of a Phillips screw, or the straight slot of a "slot head" screw. It was invented by Peter Lymburner Robertson of Milton, Ontario in 1908 (patented in 1909). Here's a link to a picture of deck screws from the Robertson company's online catalogue:

The screw is superior to the slot head and the Phillips screw. The square slot is tapered inward slightly. The screwdriver head is also tapered. This provides a tight fight with the screwdriver head. This means that you can place the screw on the driver, hold the screwdriver horizontally, and drive the screw into a wall with one hand. The tight fit makes it far less likely to strip the head on a Robertson screw than a Phillips screw. (There is an American version of the Robertson without the taper. Since there may be slight variations in screwdriver and screw size, the screw has to be slightly over sized compared to the driver, which greatly increases the chance of stripping the screw.) Due to the tight fit, you can get specialty angled screwdrivers for the Robertson screw.

The slot differs in size based on the size of the screw (which is the case with Phillips and slot head screws, too). Robertson made choosing the right size of screwdriver easy by colour-coding the handles. No. 1 and 2 screws use a #00 screwdriver with an orange handle. No. 3 and 4 screws use a #0 screwdriver with a yellow handle. No. 5, 6 and 7 screws use a #1 screwdriver with a green handle. No. 8, 9 and 10 screws use a #2 screwdriver with a red handle. No. 12 and larger screws use a #3 screwdriver with a black handle.

The Robertson screw accounts for 85% of screws sold in Canada. I never willingly bought a screw other than a Robertson, it was just so obviously superior. The next time I'm in Canada I intend to buy a big supply of the screws for home use; I already have the screwdrivers. In the U.S. it only accounts for about 10% of screw sales.

So why, if it was so good, wasn't it more popular in the U.S.? It's been largely ignored in the States due to a poor business decision that was made for good reasons. Robertson licensed his screw to companies in Europe. A British company that licensed the screw deliberately allowed their company to collapse and then snatched up the license from the trustees at a bargain. Robertson spent years and a small fortune in court in order to get back the license. In the U.S. Henry Ford tried the screw and discovered it shaved two hours off the assembly time of his vehicles. He wanted to license the screw from Robertson so that he could make sure the screws were available and so he could control their manufacture. Due to his bad experience in Britain, Robertson refused. Later, the Phillips screw came along. Phillips did license his screw to Ford, and it became the standard screw in the U.S.

Today, Robertson, Inc. has a manufacturing facility in China, with increased use of the screw in that nation. It's possible that, one day, Robertson screws will become far more popular in the U.S. I hope it happens, because it is clearly superior to its competitors.

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