About this 3D model

I want to build pulley system to drive Prusa Mendel Z-axis using only one dual shaft motor .I was looking for XL pulley for my Prusa Mendel Z drive.The only one I found is 10T XL at http://www.thingiverse.com/thing:7454So I build larger XL pulley about the size of NEMA 17 motorI use SPD/SI's Part Number:A 6Z 3-27SF03708 as my size reference.https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=41873&GroupID=218I also change the bore size from 1/4" to 5mm and using two M3 nut in the hubBelt Width 0.375"Bore Size 5mmFlange Configuration 1 Flange / With HubPitch Diameter 1.719"Outside Diameter1.700"Overall Length 0.813"