The purpose of this modification is to completely replace the stock Monoprice Select Mini V1/V2 X-Axis Carriage with a 3D printed replacement part, which will serve as a E3Dv6 compatible hot-end mount, but will also feature an integrated belt attachment and tensioning system for a GT2 timing belt. The X-Axis belt and pulleys will need to be replaced, and you will likely want to install fresh LM6LUU bearings on the new carriage, to obtain a smoother operation than stock, and avoid having to extract the existing bearings from the stock carriage.
The 3D printable files for this project can be found at the following links:
https://www.thingiverse.com/thing:2353376 (Carriage and Belt Tensioner Clamps)
https://www.thingiverse.com/thing:2049820 (Optional X-Axis Idler Pulley Alignment Clip)
https://www.thingiverse.com/thing:1848402 (Optional Clip-On Fan Shroud part from our Zero-Offset E3D Adapter)
To perform this upgrade, you will need the following hardware:
2x LM6LUU Linear Bearings
480mm (48cm) GT2 Timing Belt, 6mm wide with 2mm pitch
1x 16T GT2 drive pulley for 5mm shaft
1x 16T GT2 bearing idler pulley for 3mm shaft
Before starting this project, go to our thingiverse page and download and print out the printed components associated with this project. You will need to print the new X-Axis Carriage, the Hot-End Clamp/Fan Shroud, the Idler Pulley Alignment Clip, and the Clip on Part Cooling Fan mount (This is identical to the mount used on the Zero Offset E3Dv6 mount, so you may already have this on your printer, if you did that upgrade).
Make sure you have the parts printed and are satisfied with them before starting this mod, because you will not be able to print new parts once you have started this upgrade. Also, be sure you print the new X-Axis Carriage and Fan Shroud in a reasonably high temperature filament. Plain PLA has been known to melt in proximity to the hot-end components. Our example print is in carbon fiber filled PETG.
You will also need some fasteners for this project. You will need one 25mm M3 socket cap screw, two 16mm M3 socket cap screws, and three M3 Nylock nuts. You can use standard nuts, but we strongly recommend the use of Nylock nuts because they will not vibrate loose.
The first assembly step is to remove the existing hot-end, heather, thermistor, fans, and wiring from the stock X-Axis carriage. In these instructions the assembly instructions have been photographed with the complete X-Axis assembly removed from the printer for clarity, however, this upgrade can be done with the X-Axis installed in the printer with just the metal covers removed from the X-Axis and the Z-Axis gantry tower. The disassembly steps for the printer to get to this point have been omitted from this tutorial, because this is well documented in many other places, and is actually pretty obvious how to do anyhow.
Remove the screw holding the X-Axis Pulley to the end of the X-Axis linear rods. Set this screw and pulley assembly aside for later. You will be reusing these parts.
Gently tap on the inside of the plastic end cap for the X-Axis linear rods, until it pops off. It is just pressure fit on, and should come off relatively easily with a few sharp raps on the back side.
Remove the four M3 screws holding the X-Axis stepper motor to the gantry. Make a note of how your wiring is installed and routed, and also the orientation of the connector. You will need to note this so you can assemble it back the way it was originally installed. This seems to differ between different revisions of the printer.
Pry the plastic toothed pulley from the end of the stepper motor shaft using a thin flat screwdriver or similar tool. The pulley is just friction fit over the motor shaft, so it will just slide off with some prying force. If the pulley is very difficult to remove, you can try warming the plastic pulley with a heat source and it will expand and soften and more easily come off.
Install a new metal GT2 16T drive pulley on the stepper motor shaft. Don't fully tighten...
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