Bristol (screw)

Bristol screw

The Bristol Spline Drive is a safety screw that was developed and marketed by the US Bristol Company in Waterbury, Connecticut .

function

In the screw head there is a blind hole with a special hollow profile that is better suited for power transmission between screw and screwdriver than the hexagon hole of the hexagon socket screw . In contrast to the Allen screw, the circumferential force is transmitted via radial contact surfaces. Since there are no radial forces, there is no radial deformation of the screw head and screwdriver. Wear caused by widening the screw hole and rubbing the edges on the screwdriver, as is possible with the hexagon socket screw, is avoided. On October 14, 1913, US Patent 1,075,710 was issued to Dwight S. Goodwin.

Sizes

The screws are labeled with the outside diameter of the wrench. Bristol screws come in 18 sizes from 0.033 to 0.595 inches , of which four sizes (0.033, 0.048, 0.069, and 0.076 inches) have four undercut slots instead of six .

See also

• List of screw head drives

Web links

• Bristol Wrench Company
• US Bureau of Naval Personnel: Tools and their uses. ISBN 0-486-22022-2, p. 13

Individual evidence

1. ↑ patent specification .
2. ↑ Exists with four or six grooves.
3. ↑ List of screw sizes ( Memento of the original from July 1, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF file; 45 kB).