TronXY X5S remote driver modification

A modification of the original TronXY motor scheme, using an 8mm steel axle to place the stepper motor at the bottom and transfer the torque to a pinion that's also an easily adjustable belt tensioner.

The idea was to be able to easily adjust the CoreXY belt length and balance and to remove the horizontal load from the stepper's bearings as well.

Extra parts required (per axis):
- 8mm steel rod / linear rail, about 500 mm long
- 4mm screw and threaded brass insets for the adjustment knobs (plain 4mm screw will work too, but is not as comfortable
- 608zz ball bearing
- 2GT gear, 20T, 8mm hole
- 5-to-8-mm adapter
- T-nuts and screws (M4 x 8mm worked OK for me)

Check out these for short videos describing the idea:

Sliding ball bearing, upper mount:
https://www.instagram.com/p/B_2sYK1qjyd/

Adjusting/balancing the coreXY for parallel motion: https://www.instagram.com/p/B_24d3fIUlA/

Originally I also added a 1:1.8 belt gear, though this proved detrimental overall.