Z Axis Stepper Replacement

This is a stepper replacement for a Z-Axis lead-screw. It's designed to complement controllers that favor using a single Z-Axis stepper belted to the second screw.
It's an adapted fitting matching those used in by spauda01 http://www.thingiverse.com/thing:1001065

Hardware:

400mm 8mm Lead Screw - https://www.amazon.com/gp/product/B017AR5QBS/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
Flexible Couplings 5mm to 8mm - https://www.amazon.com/gp/product/B016KFRR0O/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
5x10x4 mm Miniature Deep Groove Ball Bearing - https://www.amazon.com/gp/product/B00ZHSTKCE/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
GT2 Timing Belt Pulley 16 Teeth Bore 5mm Width 6mm - https://www.amazon.com/gp/product/B019GI5DVC/ref=oh_aui_detailpage_o04_s02?ie=UTF8&psc=1
1 x M5x50mm Sockethead screw - Mr. Metric
4 x M5x10mm Sockethead screw - Mr. Metric
4 x M5 Square Nut - Mr. Metric

NOTE: You are going to have to measure and couple the GT2 belt to the specifications