Self-Lock threads

Just stumbled across this page: **LINK**

https://www.emuge.com/content/self-lock-integrated-thread-locking-tools

… a very clever concept.

MichaelG.

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Ref. https://www.emuge.com/sites/default/files/literature/EMUGE_2021_SELF-LOCK_Brochure-web.pdf

Edited By Michael Gilligan on 26/06/2021 07:47:38

An interesting concept. Thanks for highlighting it.

Looks excellent for permanent assemblies, but what about those routinely dismantled for maintenance?

Doh. Duplicate post.

Edited By Mick B1 on 26/06/2021 10:39:14

This seems to be the same as the patented Spiralock (TM) (Detroit Tool Industries) thread form referred to in Harold R Vaughan's excellent book 'Rifle Accuracy Facts', published in 1998. I understand that it allows the load to be shared more equally by the engaged threads, but I'd have thought that it is applicable only to once-fitted assemblies, since, presumably, considerable plastic deformation occurs on tightening.

Vaughn used it to better secure a rifle barrel to the receiver, obtaining better mechanical integrity than a normal V-thread, allowing better transmission of barrel vibrations across the joint.

It doesn't seem to have caight on, or is it a well-kept secret?

I would be very wary of using this idea on stainless fastenings. Even when lubricated stainless can cold weld with serious consequences ! Noel.

It works similar to the Dardelet thread introduced in the 1930s.

Surprisingly few comments about this...

As I understand it, the thread carries its load on point contacts (in cross-section), rather than the thread flanks. Even if the load is spread across more 'points' than the first few flanks, surely the thread can't be as strong, when loaded highly, and retain its self-locking characteristic. And, in order to spread the load across more 'points', mustn't there be considerable deformation of the 'points' that first take the load? Is this elastic or plastic deformation? Isn't this effectively just a badly-fitting, interfering, thread? If it's so good, why isn't it more widely used?

Noel -

Oh yes, been there!

The risk may be reduced where other factors of the design allow, by using different grades of the steel against each other.

Emuge Franken, Top notch gear. Have quite a lot of their End mills Drills, Taps . Very spendy though. [ thankfully I get a good discount ] but cheaper in the long run. Only drills that can rival Titex. Interesting brochure.