Ads
related to: allen wrench sizes
Search results
Results From The WOW.Com Content Network
Cap head screws of various sizes Button head screws. Hex keys are best known as "Allen keys" or "Allen wrenches" in English-speaking countries like the UK, Australia, Canada and the U.S. and in Spanish-speaking countries such as Spain and Mexico (The "Allen" name is a registered trademark, originated by the Allen Manufacturing Company of ...
A few sizes are close enough to interchange for most purposes, such as 19 mm (close to 3 ⁄ 4 inch (19.05 mm)), 8 mm (close to 5 ⁄ 16 inch (7.94 mm)) and 4 mm (close to 5 ⁄ 32 inch (3.97 mm)). In reality, a wrench with a width across the flats of exactly 15 mm would fit too tightly to use on a bolt with a width across the flats of 15 mm.
Standard 12-point hex socket bits and wrenches fit these screws. The screw heads are typically flanged, and may fit into standard Allen hex socket cap screw counterbores molded or machined into parts to be fastened. Compared to Allen hex sockets, the advantages of these bolts include higher torque capability and the lack of a recess to trap water.
An ASME B18.2.1 compliant cap screw has somewhat tighter tolerances than a hex bolt for the head height and the shank length. The nature of the tolerance difference allows an ASME B18.2.1 hex cap screw to always fit where a hex bolt is installed but a hex bolt could be slightly too large to be used where a hex cap screw is designed in.
Confusion can arise because each Whitworth hexagon was originally one size larger than that of the corresponding BSF fastener. This leads to instances where for example, a spanner marked 7 ⁄ 16 BSF is the same size as one marked 3 ⁄ 8 W. In both cases the spanner jaw width of 0.710 in, the width across the hexagon flat, is the same.
An exception to this is 4 mm hex keys, which are almost the exact same size as 5 ⁄ 32 in (3.97 mm). In many industries, this makes 4.0 mm ( 5 ⁄ 32 in) hex keys preferred for consumer products because end users can successfully use an imperial key on a metric fastener, and vice versa.