Bristol Wrench

A Bristol wrench is a fastener driving tool used on Bristol set screws, both of which were created by the Bristol Wrench Company.

Description

The body of the Bristol wrench is an L-shaped bar of metal formed from round stock, similar in appearance to an Allen wrench. The fastening end is a 4- or 6-toothed spline, which mates with a similar hole in the set screw. cite book
author=U.S. Bureau of Naval Personnel
date=1973
url=http://books.google.com/books?vid=ISBN0486220222&id=LvDpE5llCB8C&pg=PA13&lpg=PA13&dq=%22bristol+wrench%22&sig=0xHmBxJAWwcq9bk4QAUmwBF1Dqc
title=Tools and Their Uses
publisher=Courier Dover Publications
pages=p. 13
isbn=0-486-22022-2] The grooves in the wrench are cut by a square-cornered broach, giving a slight undercut to the outer corners of the driver. Compared to an Allen, the force-transmitting faces are closer to the ideal radial, thus less likely to damage the socket for a given torque. Their torque-transmitting advantage over the far more popular Torx is much less pronounced.

The Bristol Wrench Company claims that the screws are of superior design because almost all of the turning force is applied at right angles to the fastener axis. This greatly reduces possibility of stripping the head of the fastener when tightening. These fasteners are often used when softer, non-ferrous metals are required, even in extremely small sizes.

Uses

Bristol set screws are currently used in avionics, higher-end communications equipment, cameras, air brakes, construction and farm equipment, astronomy, and military equipment. At one time they were common in refrigeration equipment as well. They are frequently used to secure knobs on front panel controls or gears on shafts, where extreme tightening is required.

External links

* http://www.bristolwrench.com
* [http://www.mgs4u.com/bristol-wrench-spline.htm Bristol spline driver manufacturer's catalog]

References