I like the screw solution but I use a dremel with a grinding wheel. Spin it up on a coarse grinding wheel and dress the business end to the correct shape. Usually I make the countersink shallow then perfect it with a cutter set to the correct depth.
Reason is fiberglass is hard of steel tools.
Estes Park, CO
wirejock at yahoo dot com
Donated 01/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved (2,000+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.