"DougC" wrote in message
...
Is there such a thing? The usual places show nothing of the kind.

Countersunk-head screws fit flush with the surface of course, but another
aspect of them is that they stay centered in the holes. Is there a nut
with a conical contact area to fit similarly?

Functionally a PEM nut does the job as long as you can turn the screw
instead of the nut. A low-profile Nylok nut will go on backwards after you
form threads in the insert by installing it once correctly. You need to
push it against the male thread to start it so it may require a customized
socket or nut driver.

I've seen slotted nuts meant to fit into a recess. As I recall they were
difficult to install without a screw-holding screwdriver and needed a second
spanner screwdriver to tighten. I think they were intended for knife or gun
grips but the ones I saw came from an electronics hardware distributor. They
weren't tapered. The big problem with using countersunk flatheads to join
two parts is aligning all the holes exactly. If you don't the first screw
that's tightened will align the parts and the others will be jammed
sideways.

Another name to search for sex bolts is "Chicago screws".

jsw