Just curious, but has Riot explained how exactly Draven's Axes work?
Like do they spin because they're on some kind of rotation device, or are they part Hextech (which might explain a second blade growing out of nowhere.)
They've been touched by our Lord and Savior 
's mustache. That gives them their magical properties.
They run off a very specific technology known simply as "Dravenology", which runs off the power off of the mustache of the operator, Draven's mustache gives his axes such an immense amount of power he is able to pull off these ridiculous stunts off with them.
My best guess is from looking at the design the handle on the inside of the circle has a lock mechanism. This allows him to swing the blades open, then he can release the lock mechanism which allows the outer ring to spin freely in a certain direction (think a ratchet) this allows him to spin them with speed, then he can lock the mechanism which would allow him to throw it. It definitely would require practice but hey its the league of legends each of them has a unique talent.
As for his ultimate imagine one of those child cars you played with where you pulled them back and they would charge a a mechanism so the car would move forwards by itself, its like that but it winds itself up in both directions, and when it hits something the momentum is lost causing it to change directions. How it follows him? magnets
I've got a bit of concept art that might help explain it for you :)
http://www.videogamesartwork.com/games/league-legends/draven-blade-exploration
http://www.videogamesartwork.com/games/league-legends/draven-blade-options
So basically its two blades next to each other, one of them rotates and snaps into place, and then you use the handle to start rotating them into the whirling blades of death :)
All things done by are possible because .
the bearing ball system. Its very simple, Im surprised why people are so dumb here. =|
"Spinning is so much cooler than not spinning."
Draven's arms never get tired.
