I've had a Trioh teak/cane coffee table for a little while now. They are not so rare or expensive, but I've always liked their framing lines and exposed brass bolthead details. However, I was always a little confused as to the construction, as the bolt heads are smooth domed with no voids for any screwdriver heads.
A couple of days ago, I finally decided to see if I could disassemble it. Sure enough, the brass domes were able to be unscrewed by hand without much effort. I was surprised to find that the brass dome was only a visual cap that screwed into a threaded shaft of a slotted head steel machine screw. The four machine screws were then removed, and the table disassembled easily afterwards.
Has anyone seen this screw assembly before? Is there a name for it? While I'm a fan of exposed fasteners if elegantly done, I kind of like this pseudo-hidden detail as well. 
I have seen these before on...
I have seen these before on a D61 El Lissitzky chair.
There was a fair amount of dirt between the seat pad and the acrylic frame and I was thinking to myself how on earth do I undo these screws to remove the seat pad. So I just put my fingertip on the screw cap and jokingly asked my equally bemused husband, was I to magically remove them with my fingertip? As I gently twisted my finger, the "cap" untwisted to reveal the same fixture you have pictured! Ta-dah!
http://www.deconet.com/decopedia/template/seating/arm-chairs/D61-plexigl...
Patricia, that was pretty...
Patricia, that was pretty much my thought process as well. Since there was no exposed nut on the back side of the leg, I thought the only chance I would have to unscrew it would be to press my finger on it, twist, and hope.
The only thing missing was me saying "Open Sesame!"
These look similar.
I've not seen anything like them in the US.
http://www.screwmaster.co.uk/set-of-4-mirror-screws-with-polished-brass-...
Lee Valley
Sells them in the US, which was easy to find now that tktoo has blazed the path. Unfortunately the website doesn't have such a spectacular name as "screwmaster" like tktoo's site.
http://www.leevalley.com/US/Hardware/page.aspx?p=46598&cat=3,41306,41316...
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