Biqu B1 Linear Rails mod

Biqu B1 in comparison to Ender 3 is printer with more rigid table, more powerfull mainboard, easy way to add BLTouch and in my opinion better possibility add second Z screw (there is free place on mainboard for additional stepper driver, which can be used to control 2 Z screw independently)

Main disadvantage of Biqu B1 is very limited option to modify toolhead. There are upgrades to change extruder from bowden to direct, but without hotend change it has a lot less sense. 

This design is adapting Biqu B1 to most of modern toolheads, by changing standard carriage on Linear Rails carriage. In this way a lot of designs will be applicable to printer, like Voron Stealthburner. Personally I remixed great lightweight Ofek256 design, which is available in my projects as Cobra Toolhead (https://www.printables.com/pl/model/460657-cobra-toolhead-linear-rails-direct-drive-mount-for).

BOM:
- Linear Rails MGN12 (suggested MGN12H) - 300mm
- 7x M3 screws & t-nuts to mount Linear Rails
- longer M3 screws for X motor mount
- 2x M3 heat inserts
- Biqu B1 Z limit switch (if you are using BLTouch or any other bed leveling probe you should have unused one)

Assembly:

1. Add heated inserts to motor cover body
2. Unscrew motor
3. Unscrew Z limit switch
4. Mount motor cover body (on this step pass cable throught designed holes)
5. Mount Z limit switch on motor cover body
6. On mainboard switch cable from Z limit switch to X limit
   
7. If needed add on opposite end stopper to not fall linear rail carriage

In case if something is unclear or missing in description, please ask question in comments section.