Try searching for coarse thread socket set screw (which is the engineering term for a type of grub screw). There are lots about and I imagine a very coarse threaded one will work in wood. Trouble is you may have a problem buying just one off.
I have got some 1/4" machine screws in the workshop that I use for this purpose, they are about an inch long with a 45 degree point at one end and an allen key socket on the other. They are also black so do the job quite well.
I'll stick you a couple in an envelope if that will help.
Well its to make a projector ceiling bracket. The ceiling in my cinema is very low and I can't find a bracket thats short enough so the projector don't get in the way of peoples view when there sitting on the raised seating. This "grub screw" will just stop the brackets adjustments from moving from the vibrations of the sound. the bracket will be painted black but ill probably make it out of Ash, Oak or Beech, depending on what I find in the wood store. The grub screw will go through the face of a round plate about 15mm thick and onto another round plate but there will be room for the screw to poke out a bit.
The reason for hex is so I can use the short section of a hex key to turn the grub as I wouldn't have room to get a screw driver in there. I have an hex key shaped tool but the short side is a philips head so I could use one with a Phillips head but not slotted.
I would prefer the grub to sink rather then poke out but its not to much bother if it pokes out. The round plate will be over 100mm in diameter so an insert would have room however the grub location will be way off centre so a lath turned thread would be out of the question.
Roger, if you think the ones you have would do the job then yes please.
I recollect that I used a standard M6 threaded bolt (or something similar) in wood a couple of years ago for a little project...it does help if the timber is very dense and heavy so a decent thread can be cut. I was using African Blackwood at the time with no problems...the stuff is so hard it can almost be treated like a metal anyway - Rob