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I'd like a (hex) cap screw that at the non-head end has a (smaller) keyed opening, allowing tightening the screw from the inserted end (because the screw will be into a threaded hole with an open end, and I can access the other side more easily after partially tightening from the capped end).

I'm imagining something like this:

Double socketed cap screw

Do these exist, and if so, what should I search for to find them?

chrisb2244
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    Good luck with that. I don't think these exist. It's a very odd requirement. There are double-ended setscrews, however. You could always cut a slot into the threaded of the screw for a flat head. Good luck not damaging the thread though and you would need a lathe to fix that. Do you have little clearance for tool access on the head size of the screw or something? – DKNguyen Feb 25 '22 at 03:29
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    This smells of bad system design. If a screw will need adjusting, the container/structure should have cutouts to allow direct access. – Carl Witthoft Feb 25 '22 at 13:45
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    @CarlWitthoft see at 17mins how Kurtis gets the bolts out. https://www.youtube.com/watch?v=11yJG2D-wRg – Solar Mike Feb 25 '22 at 14:26
  • @SolarMike point taken :-) . – Carl Witthoft Feb 25 '22 at 14:57
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    I say slot the non-head end and hit it with a thread-file. A thread-file works nicely to clean-up the threads of a a screw that has been damaged (even rusted). They usually have 4-different thread repair "files" per end, thus 8-total. They come in English and Metric. See https://www.mcmaster.com/thread-files/ for example. – Jim Clark Feb 25 '22 at 23:46
  • @JimClark Interesting. I knew rethreading dies existed but not files. Right, I guess I forgot those existed too when I mentioned a lathe would be needed to fix a damaged thread in my first comment lol. – DKNguyen Feb 26 '22 at 04:51
  • If you use a die install upside down, cut the slot, and remove die. That way it cuts threads during removal. – Jim Clark Feb 26 '22 at 20:33

2 Answers2

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They do exist - special applications only, seen some on a line borer clamping system.

However I would make them if needed by taking grub screws - which does not have a head but does have the inserted hex, then weld a nut to the other end. Even a nut with the built-in washer may work well.

So Check the video at 17 mins 11 secs for the bolts being removed: https://www.youtube.com/watch?v=11yJG2D-wRg

Solar Mike
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0

McMaster-Carr replied to my query with a minimal answer, "We don't carry that type of screw." Unfortunately part of my question (unanswered) was a suitable designation for the type of screw, to facilitate searches.

On the DIY aspect, consider to use a suitable length set screw to match your requirements, and a nut on the "cap screw" end, held in place with red threadlocker adhesive. I realize this does not qualify the hex wrench aspect for both ends.

To accomplish that goal, things get even more DIY, as one would use a threaded coupler on the flat end of the set screw and a cap screw on the coupler, all held in place with red threadlocker adhesive.

fred_dot_u
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