Arrowhead for Mini Cross Bow

This is an arrow for crossbow http://www.thingiverse.com/make:283084. It is the first thing I have designed in FreeCAD so if this copies anyone else design I apologize as it was a learning tool.
In order to make the fins thin I had to double the size in FreeCAD so when you print it the scale of the shaft needed to be .5 and the scale of the head needs to be .6 - this sizing is already saved in the stl so no changes needed before print.