Although I'm looking at styrene shear pins to keep a nose attached to a 
payload bay during single deployment, I've seen a lot of references to nylon 
screws and wondered ...

- the rivets and screws I've found via the links posted in this newsgroup 
all have heads that look as if they'd stand proud of a rocket surface. 
(Skiffy rivets look countersunk but the way they're fixed suggests they 
stand off the surface by 1mm or so, and the nylon screws at RS Components 
seem to have "cheese heads" which aren't countersunk anyway). Is this corect 
and doesn't it cause unwelcome airflow effects?

- If so, do you cut the heads off?

- I've seen reference to sheet metal or self-tapping screws for some 
fittings but presumably nylon screws won't cut their own threads (especially 
in PML quantum tubing which I'm currently using). Do you "screw" them in 
without a thread or do you cut a thread perhaps with a self-tapping screw 
beforehand?

Thanks for any insights you might have.

Kevin