Biqu H2 Rail Mount (v2)

18Jul2023 Update:

I finished the redesign and made more room for the pieces to adjust to rails that are slightly off-spec (they still need a 20x20 screw pattern) and made the 2 pieces fit together easier.

For the belt attachment I ended up making 2 variations.  The files called “bottom_belt”, the belt attaches under the X gantry as normal on most printers.  The files called “top_belt”, the belt attaches above the X gantry.  I think it is easier to connect the belt on the top and saw no reason not to do that.  Attaching the belt above the gantry requires reversing your X stepper direction either in firmware (very simple in Klipper, Marlin requires re-flashing) or by swapping 2 wires on the stepper cable.  There are plenty of resources available on the internet if you need help with either of those options.

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***NOTICE: IF YOU CONNECT THE BELT ABOVE THE X GANTRY YOU HAVE TO              *** ***REVERSE THE DIRECTION OF THE X STEPPER EITHER IN FIRMWARE OR BY             *** ***SWAPING 2 WIRES ON THE STEPPER CABLE!!!!!!!!!!!                                                          ***

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I found that the belt grooves printed best when they were laying down parallel to the build plate but I included a small test block with the same belt groove you can print in different orientations to see what prints best on your printer.

The only support needed is a small one on MGN12H_Mount_Bottom_Belt_(v2) where the notch for the endstop is.  The wire groove on the side might drop a couple strands if you want to paint in support there but it will not affect function and will be hidden by the wires.

I could not get an adjustable endstop for the top belt version so I included files for 5, 7, and 9mm which should meet most peoples needs.  

F360 files and step files are included if you want/need to adjust something.

Printing specs:

I have printed these with bot PLA and PETG and both feel fine with the following settings:

Layer height : 0.2

Perimeters : 4

Infill : 42%

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17Jul2023 Update:

I encountered some issues with this and am making some significant changes.

– I ended up not liking the belt connection so that is getting a complete makeover.

– I tried mounting it on a carriage from a different manufacturer and the holes were about .5mm off so I need to make it able to shift a bit to accommodate carriages made to different tolerances.

Hopefully it will only take me a couple days to get it back to what I would consider acceptable.

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In the process of a complete overhaul of my old Ender 3 Pro I decided to use the MAD fan system (thanks to @Predy and everyone that worked on that) but still needed a rail mount.  Since I could not find an acceptable one (and saw a lot of other people looking for one in comments) I decided to take a stab at making one.

This one is quite compact and only pushes the hotend about 9.3 mm out from the face of the rail carriage (14mm from the rail).  I included holes for zipties and a groove along the left side and top to help with cable management.  The groove is not intended to completely encase the wires, it is just a guide to help keep them from shifting.

I am using a custom relocation bracket to move my endstop switch to just below the rail so I cannot verify if the included endstop will hit a stock mounted switch.

No support is needed if oriented according to the included pic.  

The 5.7 mm heatset insert in the grooved belt platform sticks out a bit but does not affect performance ( no matter which side sticks out).  Platform is only 5mm thick and I did not have shorter inserts on hand. 

I have included the .stl, .stp, and .f3d if anyone needs (or wants) to tweak them.

It includes:

MGN12H_Mount – mounts directly to the rail carriage

H2_Toolhead_Mount - mounts to the H2 hotend and then to the rail mount

End_Stop - An X-axis endstop with a little bit of adjustability, mounts to bottom left of the rail mount

Belt_Clamp _ Screws onto the grooved platform of the toolhead mount to smash the belt into the grooves.

Hardware required is:

5 x M3 x 5.7 heat set inserts

10 x M3 x 8mm countersunk screws

1 x M3 x 8mm socket head cap screw (for the end stop)

zipties (all 5 ziptie holes are 1.5 x 4 mm)

Printing specs:

I have printed these with bot PLA and PETG and both feel fine with the following settings:

Layer height : 0.16

Perimeters : 4

Infill : 42%

These parts have very tight tolerance so depending on your printer's accuracy or amount of stringing or other imperfections, you might need to do some light scraping to get good a fit.

I am still waiting on my new control board so I have not been able to actually print with this yet but I have completely mounted it and moved everything around and have not seen any problems.  Let me know if you find a problem or notice something I missed.

This is my first Fusion 360 project (a few years exp with FreeCAD) so don't trash me too hard if you are inspecting the f3d file and you think I did things “wrong”.