all the fellers and fellerettes who have helped me out in the past and
A Keps nut, (also called a K-nut or washer nut), is a nut with an
attached, free-spinning washer. Keps is a trademark of ITW Shakeproof.
The name comes from "kep" in Shakeproof, and the "s" is because usually
more than one are purchased. It is used to make assembly more
convenient. Common washer types are star-type lock washers, conical, and
A screw and washer assembly. A screw or bolt which has a captive washer.
The washer is frequently loose on the plain shank of the fastener, the
shank diameter being equal to the effective diameter of the thread; the
thread being rolled from this diameter. The origin of the word is a
frequent question. In the 1930's E. C. Crowther was a representative for
a company that sold both shakeproof washers and screws. He came up with
the idea of placing the washer on the screw before it was thread rolled.
The major diameter of the screw being larger than the washer hole
prevents it from coming off. The Illinois Tool Works made machines that
produced these patented pre-asSEMbled washers and screws. The s at the
end of SEMs is thought to have been subsequently picked up because they
are not usually purchased individually. In spite of the original patents
and trademarks the word SEMS is generally recognised as a generic term
applicable to screw and washer assemblies.
ITW is a diversified manufacturer of highly engineered components andindustrial systems with $16 Billion in revenues. ITW Shakeproof was
formed in 1923 upon the invention of the Shakeproof twisted tooth
lockwasher. Over the last 86 years, Shakeproof inventions have become
industry standards such as KEPS nuts and SEMS screws. ITW Shakeproof
currently offers a full range of internally and externally threaded
metal fasteners across a broad size range.
Illustration from another ITW patent:
The exemplary nut (20) of FIGS. 5 and 7 includes a washer (24)assembled therewith. In other embodiments, the nut does not include the
slots or washer.
And that's my book report for the week...