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Robertson screwdriver

 
Robertson Screwdriver

 
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Robertson screwdriver
 
 
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A Robertson screwdriver (also called a square drive screwdriver) is a type of screwdriver
Screwdriver

The screwdriver is a device specifically designed to insert and tighten, or to loosen and remove, screws. The screwdriver is made up of a head or tip, which engages with a screw, a mechanism to apply torque by rotating the tip, and some way to position and support the screwdriver....
 with a square
Square (geometry)

In Euclidean geometry, a square is a regular polygon with four equal sides and four equal angles . A square with vertices ABCD would be denoted ....
-shaped tip with a slight taper (in the same way that flatheads, Phillips, hex
Hex key

A hex key, also known as an Allen, zeta, or Unbrako key or wrench, is a tool of hexagonal cross-section used to drive Screw#Fasteners with a non-tapered shafts and screw#Fasteners with a tapered shaft s that have a hexagonal socket in the head ....
, and Torx
Torx

TORX, developed by Camcar LLC of Acument Global Technologies , is the trademark for a type of screw head characterized by a 6-point star-shaped pattern ....
 have flat, x-shaped, hexagon
Hexagon

In geometry, a hexagon is a polygon with six edges and six Vertex . A regular hexagon has Schl?fli symbol ....
al, and hexagram
Hexagram

A hexagram is a six-pointed geometric star figure, or 2, the compound of two equilateral triangle s. The intersection is a regular hexagon.While generally recognized as a symbol of Jewish identity it is used also in other historical, religious and cultural contexts, for example in #Use of the Star by Arabs and Muslims, and #Occurrence in...
mal tips, respectively). Robertson screws are used mainly in Canada
Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
 (where they are very common), though they can be found elsewhere.

Canadian P.L. Robertson invented the Robertson screw
Screw

A screw is a shaft with a helix groove or screw thread formed on its surface and provision at one end to turn the screw. Its main uses are as a threaded fastener used to hold objects together, and as a simple machine used to translate torque into linear force....
 and screwdriver in 1908.






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Encyclopedia


A Robertson screwdriver (also called a square drive screwdriver) is a type of screwdriver
Screwdriver

The screwdriver is a device specifically designed to insert and tighten, or to loosen and remove, screws. The screwdriver is made up of a head or tip, which engages with a screw, a mechanism to apply torque by rotating the tip, and some way to position and support the screwdriver....
 with a square
Square (geometry)

In Euclidean geometry, a square is a regular polygon with four equal sides and four equal angles . A square with vertices ABCD would be denoted ....
-shaped tip with a slight taper (in the same way that flatheads, Phillips, hex
Hex key

A hex key, also known as an Allen, zeta, or Unbrako key or wrench, is a tool of hexagonal cross-section used to drive Screw#Fasteners with a non-tapered shafts and screw#Fasteners with a tapered shaft s that have a hexagonal socket in the head ....
, and Torx
Torx

TORX, developed by Camcar LLC of Acument Global Technologies , is the trademark for a type of screw head characterized by a 6-point star-shaped pattern ....
 have flat, x-shaped, hexagon
Hexagon

In geometry, a hexagon is a polygon with six edges and six Vertex . A regular hexagon has Schl?fli symbol ....
al, and hexagram
Hexagram

A hexagram is a six-pointed geometric star figure, or 2, the compound of two equilateral triangle s. The intersection is a regular hexagon.While generally recognized as a symbol of Jewish identity it is used also in other historical, religious and cultural contexts, for example in #Use of the Star by Arabs and Muslims, and #Occurrence in...
mal tips, respectively). Robertson screws are used mainly in Canada
Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
 (where they are very common), though they can be found elsewhere.

Canadian P.L. Robertson invented the Robertson screw
Screw

A screw is a shaft with a helix groove or screw thread formed on its surface and provision at one end to turn the screw. Its main uses are as a threaded fastener used to hold objects together, and as a simple machine used to translate torque into linear force....
 and screwdriver in 1908. He received a patent
Patent

A patent is a set of exclusive rights granted by a state to an inventor or his assignee for a term of patent in exchange for a disclosure of an invention....
 in 1909, and later applied for and received other patents. The last patent expired in 1964.

Robertson screwdrivers are easy to use one-handed (i.e., without using the second hand to hold the screw); in fact, the chamfered socket stays firmly on the screwdriver even when it is shaken. They also allow for the use of angled screw drivers and trim head screws. The socket-headed Robertson screws are self-centring, reduce cam-out, stop a power tool when set, and can be removed even if painted-over or old and rusty. In industry, they speed up production and reduce product damage.

Robertson had licensed the screw in England
England

native_name =|conventional_long_name = England|common_name = England|image_flag = Flag of England.svg|image_coat = England COA.svg|symbol_type = Royal Coat of Arms...
, but the party with which he was dealing intentionally drove the company into bankruptcy and purchased the rights from the trustee, thus circumventing Robertson. 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
Henry Ford

Henry Ford was the United States founder of the Ford Motor Company and father of modern assembly lines used in mass production. His introduction of the Model T History of the automobile revolutionized transportation and American industry....
 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 supply of screws would not be guaranteed and stopped using them.

Recess dimensions


Robertson-head screwdrivers are available in range of tip-sizes. A given driver's suitability for use with a particular size of screw and recess size is indicated upon its handle according to the following colour code:

style="color:black;" | Recess dimensions
Color Screw types Fraction Min Max
Orange (#00) No. 1 & 2 1/16 in.+ 1.77 mm
(0.0696 in.) 		1.80 mm
(0.0710 in.)
Yellow (#0) No. 3 & 4 3/32 in.- 2.29 mm
(0.090 in.) 		2.31 mm
(0.0910 in.)
Green (#1) No. 5, 6 & 7 7/64 in.+ 2.82 mm
(0.111 in.) 		2.86 mm
(0.1126 in.)
Red (#2) No. 8, 9 & 10 1/8 in.+ 3.34 mm
(0.1315 in.) 		3.38 mm
(0.1330 in.)
Black (#3) No. 12 and larger 3/16 in.+ 4.81 mm
(0.1895 in.) 		4.85 mm
(0.191 in.)


Footnotes


External links

  • official web site