I finished it 2 days ago. It works fine and dandy in practice too. :D
http://postimg.org/image/cbf9tuzqj/
It's also made in compact 3x3x23 dimensions, fully controlable from flight mode with functions automine, stop and mine by hand. All controls are button mash resistant(logic wont fuck up if you mash buttons). It automaticaly retracts at MAX rotation speed to it's first shape when turned off. Storage block is accessible from above, so it's very easy to put it on a ship as a hidden arm that comes out of bottom at our afk times. It seems much more practical now to install it as an extending arm than a drone because carrier with many of those would have unwieldy controls because of wireless block limitations. It's mining pattern is ugly because of beam-rails bug, already shoting beam keeps shoting at it's first target instead of trailing with rails, but that isn't a problem for functionality of this system. Only problem is that game loads it wrong(which I noticed now when taking that screenshot), so it doesn't function after being loaded, but I'm gona work on that.
So Loadout, in the final version I made red axis rotate at 50%(1/4) and blue one at 22%(1/9) speed. That does not draw a spiral. It draws a
flower with 2 times more petals than one which I happened to draw for you on first picture(9 petals, picture has 4+
/\W). Flower on picture has different number of petals cause I was experimenting with different speeds at that time.
I honestly think that logic part of this isn't a problem for you guys, just realize how it works and you got it.