On Saturday, February 3, 2018 at 11:21:17 PM UTC-5, Charles Longley wrote:
The head diameter on that screw is too big. I need a 4 mm screw with a head diameter around 6.5 mm. I am not sure what the countersink angle is. Looks closer to 100 though.

If it is not 90degr., then it is not likely to be a metric screw! Just because the Blanik is from Europe doesn't mean that the hardware they used on that glider is metric. My Caproni was made in Italy and it uses all imperial sized hardware.
Uli
'AS'