MK3 to MK4 Z-Axis 8mm (keep all 8mm rods and bearings)

These parts allow you to use the new MK4 parts on your stock Prusa MK3/S/S+. There is no need to buy new rods or bearings, but you will need some extra bolts, nuts and a slightly longer x belt . As the MK4 has a wider X carriage you will need to print all parts.

I have upgraded my own MK3S+ with these parts and it works fine. You will need to run the calibration wizard again as the Z height and X travel will change slightly. I also took the opportunity to replace all the bearings on the X and Z axis.

To use the stock LM8UU bearings, print two of the spacers (stock) and insert them between the two bearings. If you purchase LM8LUU bearings, print two of the spacers (LM8LUU). See the images for reference.

Important:

- Due to geometric constraints, I had to replace two hex nuts with captive nuts in the X-end-motor and X-end-Idler. Use M3x18 screws for them. - X-end-idler & X-end-motor: Do not tighten the upper screws completely, leave a gap of 1mm. Once the X-rods are in place, they can be tightened. - The rubber pads (bearing mount) need to be a bit smaller to fit properly. Cut them to 17x9x1mm instead of 20x10x1mm. - As I had no axle, I also changed the idler bearing mount to a screw like on the MK3. - In the preview above, the holes for the rods etc. are not rendered correctly. This is because they are negative volumes in the .3mf file. Follow the assembly instructions from Prusa . You can print the this tool to lube the bearings. Make sure you also print out the X-Holder tool before you disassemble the printer and read the instructions carefully!

Parts you need

Prints:

- 1x X-Holder - 1x Bearing luber - 2x Spacers according to your needs (Stock or LM8LUU) - 1x All parts of MK3_to_MK4_8mm.3mf Mechanical:

Use the values in brackets if you're not reusing the nuts and screws from your MK3/S/S+.

- ( 1x) | 1x Belt for X-Axis about 900mm GT2 6mm width - ( 4x) | 4x M3x30 screw - ( 1x) | 1x M3x25 screw - ( 1x) | 1x M3x20 screw (This screw is for the bearing housing 623H) - ( 7x) | 2x M3x18 screw - ( 4x) | 4x M3x16 screw - (23x) | 5x M3x10 screw - ( 9x) | 9x M3nS nut - ( 4x) | 0x M3n nut - ( 1x) | 0x M3nN nylon nut - ( 4x) | 4x Rubber pad 17x9x1 mm - ( 2x) | 2x Rubber pad 40x40x2 mm You may be lucky with the spare parts that came with your MK3/S/S+. I used a piece of bicycle inner tube for all the rubber pads.

Print instructions (provided by Prusa)

Download the latest PrusaSlicer and use the following settings**:

- Print settings: 0.20mm QUALITY - Filament: PETG (tested on Prusament) - 15% Grid infill ** Note that print settings are recommended, but you can experiment with your own.