Awblain - if your gyro precession theory was correct, we wouldn't need to change the pitch of the blades and could do without feathering hinges altogether.
All we would need is a hydraulic ram to exert a linear force 90 degrees before the desired blade position, give it a poke or pull and let precession do the rest.
It doesn't work like that, as you can tell by looking at pretty much any helicopter in the world - we need the feathering hinges (or similar aerodynamic device like tabs) to change the pitch on the blades because it is the aerodynamic forces that dictate where and how the blades move, not gyroscopic precession.