This is an X-axis replacement I made for my Tevo Tarantula (but will work for any 2040 extruded aluminum setup).
I took the inspiration from http://www.thingiverse.com/thing:1580899 and modified it to be easier to print and use a single idler wheel instead of the 2 dinky ones that come with stock Tarantula.
1 - Idler wheel
1 - M5 25+mm w/nut for tension wheel
4 - M4 20mm w/nuts
- 1 of these should either be a flat headed screw - for the idler axle
- or you could use a thin wedge nut instead (just flip the idler wheel carriage before printing to make sure the screw head side is on the outside - if needed like on Tarantula)
Here's the idler wheel I use. *(these are readily available cheaper as well)
You do not need any extra spacers for the idler wheel, this design has it built into the idler carriage.
Minimum supports are needed for the shell.