Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4321295.
Parts to convert the Kingroon KP3 X Axis from 20x20 V Slot Rail over to a Precision Linear Rail system (Like the Y Axis). These parts allow you to remove the V Slot Rail entirely, and replace it with an inexpensive (under $20USD) 250mm long MGN12H Linear Rail kit (such as the one here:
https://www.amazon.com/gp/product/B07GBNTJW3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
In addition to these parts, you will need a 4x M4x15 screws, and ideally an M4 Tap to put some threads in the rail's pre-drilled holes. If you don't have the ability to do this - some M3x20 screwes with Locking Nuts will also work. Transfer the X Axis Belt Pulley over to this part, and flip the X Axis End Stop switch to the inside of the cover to which it mounts.
The X Carriage can be mounted to the MGN12H Carrier by drilling a few holes in the stock metal part, or you can print one of the many designs for the CR10 Linear Rail conversions found here in Thingiverse.
If you found this useful, please donate what you think it is worth to my paypal.me. Help cover the time of design. Thanks, Enjoy!