About this 3D model

This is a shaft for the big spool holder of Mark Wheadonhttp://www.thingiverse.com/thing:761893 I designed it to use it with FormFutura filament spools.Update 2016-01-04: I mentioned that it also fits to ColorFabb's filament! The outer diameter is 52mm.The length is 100mm. (v1 - v3)The length is 115mm. (v4)The large diameter where the spool is placed is about 65mm in length. There are 4 versions of it. v1 was the first design v2 was optimized regarding the necessary filament (supports are not symmetric between inner shaft and outer diameter) v3 was optimized to split the printing time (split into two parts, female and male) v4 is the same as v3 but instead of 65mm width or length it is now 80mm, because I got one spool which is 80mm wide