Robertson screwdriver
From Wikipedia, the free encyclopedia
| Part of the series on | |
|---|---|
| Screw draw types | |
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Slotted |
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Phillips |
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Pozidriv |
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Torx |
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Hex |
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Robertson |
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Tri-Wing |
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Torq-Set |
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Spanner Head |
A Robertson screwdriver is a type of screwdriver with a square-shaped tip with a slight taper (in the same way that flatheads, Phillips, hex, and Torx have flat, ×-shaped, hexagonal, and hexagrammal tips, respectively).
Canadian P.L. Robertson invented the Robertson screw and screwdriver in 1908. He received a patent in 1909, and later applied for and received other patents. The last patent expired in 1964.
Robertson screwdrivers are known for holding screws in place, even when they are not being held, and they also allow for the use of angled screw drivers and trim head screws.
Robertson screwdrivers have a colour-coded handle for easy selection as different screw sizes require different size tips. The colours and their associated screw sizes are:
- Orange (#00) — No. 1 & 2 screws (uncommon)
- Yellow (#0) — No. 3 & 4 screws
- Green (#1) — No. 5, 6 & 7 screws
- Red (#2) — No. 8, 9 & 10 screws
- Black (#3) — No. 12 and larger screws
Robertson had licensed the screw in England but the party with which he was dealing intentionally put the company under and purchased the rights from the trustee thus circumventing Robertson[citation needed]. He spent a small fortune buying back the rights. After that he refused to ever allow anyone to make the screws under license. When Henry Ford tried out the Robertson screws he found they saved considerable time in the production of cars but when Robertson refused to license the screws to Ford, he realized that the use of the screws would not be guaranteed and stopped using them[citation needed].
