Why did I mount the skateboard axles on a lazy susan? 

Hopefully HTML will let me explain this.  Imagine a top down view for the skateboard.

When neutral (not turning) the axles look like this:

|----|

When turning in (lets say in is toward the top of the screen), the axles turn inward:

/----\

When turning outward, the axles pivot the other way:

\----/

And the pivoting wasn't a few millimeters, they rotate a inch so a fixed mount wouldn't work.  There may be a better solution out there but this was easy and could be bought at Home Depot / Menards.