KEPS & SEMS Ffasterners

Too much info, but interesting if you're into mechanical assembly -- for all the fellers and fellerettes who have helped me out in the past and future....

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... 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 flat washers."

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... SEMS 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.

From

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ITW is a diversified manufacturer of highly engineered components and

industrial 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.

Patent illustration:

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And that's my book report for the week...

Reply to
Snuffy "Hub Cap" McKinney
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Reply to
Jim Wilkins

"Snuffy "Hub Cap" McKinney" wrote in message news: snipped-for-privacy@earthlink.com...

That's what I was saying in the other post- the washer spins, but the beveled shoulder area doesn't. It's just the keeper for the washer.

Nice completion of a homework assignment, though :-)

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SC Tom
Reply to
SC Tom

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Ah, but then we have that invention of the Devil, used both as a nut and as a keeper on plastic studs: The Tinnerman Nut:

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Fast installation, cheap, simple - and damned near impossible to remove wit hout damage to the stud. The "technique" is to squeeze the nut until the te eth disengage the stud and slide it up. As they are made from spring steel, they will either crack, or slip out of the grip of whatever pliers are use d.

Mr. Albert H. Tinnerman... the inventor of same nut, should have been diver ted to a monastery in early childhood, and allowed no tools sharper than a rubber spoon!

Peter Wieck Melrose Park, PA

Reply to
pfjw

I have removed a lot of them with a pair of 90 degree dental picks. Slip the tips under the springs from opposite sides and against the post, then gently tilt the picks to release their grip. The only time it didn't work was when someone hd tried another method ands had already cut most of the way through the plastic post.

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Reply to
Michael A. Terrell

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