MGN12 Carriage - MK3 hotend only for 4020 Extrusions (Tevo Tarantula)

thingiverse

I've been on a quest to find a smaller hotend assembly for quite some time now. I experimented with vertical carriages when the wheel was on the X axis, but after getting my hands on MGN rails, I hit a major roadblock: most carriages didn't take into account that if you mount the E3D V6 hotend too far up, the nozzle can't touch the bed because the 4020 extrusion gets in the way first. So, I stumbled upon this nice remix but it had the same problem, the nozzle couldn't touch the bed. The hotend fan is a 40mm fan. I made some modifications to the carriage mount to provide about 1-2 cm of clearance for the nozzle, just to be on the safe side. The carriage seems to have been originally designed for machines where the belts run vertically instead of horizontally, so I also added belt locks where needed instead of using the vertical belt loop method. I did keep the screw holes that were originally intended for this, though. You can use these with M3x10 or M3x8 screws to provide two small posts for cable strain relief on the carriage cables. I also added a mount for the endstop switch. I'm aware that the switch hits the wheel instead of the acrylic, but in my case, I just don't have the upper inner wheels on each side, and tightening the X axis was far easier like this. Even if you don't take the wheels off, the endstop should trigger on the wheel, and you'd only lose a couple of mm's worth of X axis. The original carriage used a 5015 radial fan, but I had a 4020 lying around that I'd used for the Radial Fang fan, so I just modified the carriage lid to work with the 4020 fan. I included the original 5015 files for the lid and layer fan in case you want to use these. There are versions of the carriage lid with and without the BLTouch mount. In my case, there was no need for washers between the BLTouch and the carriage mount. The offset for the BLTouch is: X = +34, Y = 0. I included STEP files for everything that I modified.