How are set screws made? 1

[steris]

So this is something that I have been curious about for a long time and never figured out. When you use a metal or plastic set screw, they can have a hex recess for an Allen wrench. How is recess this made? I would have guessed that the hex is punched in while the part is just a cylinder. I know that the threads are roll formed so punching the hex head (I think) would cause mushrooming and hinder the thread rolling. Intuitively, it seems that machining it in would be way too expensive given the cost of these parts. The metal parts are obviously not cast or forged. Also, is the process different for metal fasteners versus plastic ones? Just something that had been bothering me since college. Sorry if this isn't exactly the right forum but it seemed to be the most appropriate one. Thanks!

-Steris

 

[HDS]

https://secure.wikimedia.org/wikipedia/en/wiki/Unbrako#History

 

[drawoh]

TenPenny,

You are thinking of the book One Good Turn, a history of screws in general. I think he was looking for the earliest screwdriver.

--
JHG

 

[JohnRBaker]

Trust me, I have nothing against Phillips-head screws. In fact, I've often replaced slot-head screws with Phillips-head when reassembling something simly because I think they are much easier to remove and reinstall, particularly IF you're going to be using a cordless driver.

BTW, I've seen Robertson style screws in places where I suspect they were used to prevent, or at least deter, someone without the proper tools from removing some cover or something. However, recently I've noticed some stuff coming out of Europe using so-called TORX security screws...

...so now I've had to add some additional bits to my collection.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
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