MXL Belt Bowden Extruder 1.75mm

This is a remix of a solid design by pefozzy. I liked that it supports the hobbed bolt really well with 3 bearings as opposed to two in conventional wade extruders. I also liked the belt driven aspect. One problem I had was sourcing the closed loop belts in the US. My solution was to use MXL belts since they're cheap and easily available. I used a 95MXL belt from McMastercarr for $2.70 a piece: http://www.mcmaster.com/#mxl-series-timing-belts/=uwpq7n.

I found on my lab robot/3D printer con