V1.8_Z_Rails_Mod

Z Linear Rail Mod for Voron 1.8 (300x300x250)

Parts list:

• 2 modified z motor mounts (printed in abs with the standard voron settings)
• 2 leadscrew-mgn12 blocks (printed in abs with the standard voron settings)
• 2 mgn12h (300mm long for 250 z)
• 4 m3x16 shcs (fasten lead screw nut to block)
• 4 m3 nuts (fasten lead screw nut to block)
• 12 m5x16 bhcs (fasten blocks to extrusions and extrusions to frame)
• 8 m5 t-nuts
• 8 m3x20 shcs (fasten blocks to mgn12's)
• 2 Misumi HFS5-2020-340-TPW (vertical extrusions for 250 z height)
• 12 m3x8 shcs (fasten mgn12 to extrusion)
• 12 m3 t-nuts
• 2 Misumi HFS5-2020-350-AH10-BH340 (x extrusions for 300x300 bed frame)

Notes:

The z motors are shifted inwards 2.07 mm (towards the center of the bed) so you must modify the deck panel slighly. This was necessary to provide clearance for the rails. See the dxf folder for the modified dimensions.

The y extrusions have an allen key clearance hole drilled 170.8 mm from the front end cut. This is for the blind joint that fastens the new extrusions the mgn12's are mounted to. These 2 extrusions are in line with center of the bed. It is very important that the end cuts are square and exactly the same length. This can potential bend your gantry extrusions if they are not square. I did not have any issues with Misumi's end cuts. Others have used right angle brackets with success and this might be a better way.

I've added leadscrew-mgn12 block stl's for both the 300 and 250 build sizes so choose accordingly. I had trouble with warping when printing the leadscrew-mgn12 blocks on my ender 3 with a glass bed. Elmers purple gluestick on the buildplate saved the day. These blocks have been tested with the link cnc 8x2 and bigtreetech 8x8 integrated lead screws. I highly recommend the bigtreetech 8x8 lead screws with the only downside being that the bed drops slighly when the motors turn off.

You can center the mgn12 to 2020 extrusions using the stl located in the switchwire repo here.

The 2 bed extrusions in the x direction are shortened to 350mm because they're no longer necessary to hold the lm8luu bearing mounts. Although the stock length extrusions (420mm) will still work, they will be protruding out in space.

Let me know if you have any questions or need anything. There is also a video of my mod on youtube if you would like to see it in action.