When we were in the design phase of our decoy, we tried several different ways to attach the wings. We originally wanted to use a pin to make the wings as easy to detach as possible. The problem however is that despite using the tightest tolerances, that method allowed slight movement in the wings which translates into noise when they start spinning. Unacceptable!
The solution was to mill flat spots in the shaft and attach the wings with thumb screws. This ensures the wings are always in the same position and locked down. The result is a great looking decoy with wings that will silently spin in a 3 MPH wind.
Remember to position your wings with the cupped part of the wing facing forward. If you need replacement thumb screws or just want to carry some spares, use 1/2 inch long 8/32.