Single Motor Gantry Lift System for the MK3s [Updated]

Prusa/PulseXE/Clone Single Motor Gantry Lift

[Updated 7-03-2025] New Z axis belt tensioner

https://www.printables.com/model/1343663-pulse-xe-dual-gantry-belt-tensioner

Please leave a “Like” it helps me, Thank you!

The Problem:

Z – axis lift gantry becomes out of sync during usage, nozzle to bed height becomes random either loosing bed adhesion or driving the nozzle into the print surface. Auto leveling between print layers/prints is just not realistic. Running both stepper motors from one driver will not keep gantry level.

Aligning the bed before each print is a bandaid solution to a problematic design. You can't adjust alignment in the middle of a print. Even with closed loop motors, the bed angle can still change and lead to a failed print. The printer companies all know this, yet they continue to release printers with dual motors because they sell better. 

The Solution:

Single stepper motor dual Z-axis gantry lift system.

Notes:

I have tested to over 55,000 prints at the time of this writing without a single readjustment. I have dropped the driver current from 1.2A to 1.0A, preforms perfectly with less power. Z – axis pillow blocks are longer in order to keep the T8 shafts from bending. The two stepper pillow blocks mount in place of the z-axis motors, these are the longer 65mm blocks. The one short 30mm block is used a a belt tensioner next to the drive motor. You will need to cut a short piece of T8 lead screw for the 30mm belt tensioner block and add the two lock collars on either side of each of the bearings. It is suggested to repack your Abec 9 bearings with TinkSeal. This will give permanent lubrication as well as help seal out plastic abrasive dust. Use dental pick to carefully remove the rubber bearing seals. This will save you a headache down the road. Miscellaneous hardware will be needed depending on the size used. I suggest picking up a multi pack of bolt and T-nut hardware. I originally used M3, but this is too light for long term use.

I published this modification June 13, 2021 and it has helped many people, with many different models of printers. I hope it continues to help others. 

[Updated 7-21-2025]

2 - 65mm Stepper pillow blocks Long Dragon Bearing Mod to work with upgraded flanged bearings available on Amazon. 

1 – 30mm Stepper pillow block short (optional if used without new bearing tensioners)

1 – Nema 17 48mm LDO/E3D stepper motor (same as x-axis motor)

4 - Squash ball feet:
https://www.thingiverse.com/thing:4626207

3 - 60 Teeth 8mm Bore Aluminum Timing Pulleys

1 - 60 Teeth 5mm Bore Aluminum Timing Pulleys

2 - Nema 17 Stepper Motor Mounting Bracket, 304 Stainless Steel

1 - Timing Belt L=800mm W=6mm 400 Teeth in Closed Loop

4 - Lock Ring 8mm Shaft Lock Collar T8

6 - 608 RS Bearings (RS = Rubber Seals)

1 - TinkSeal.com Bearing lubricant

1 - Dentist Pick

2- T8 600mm Lead Screw (cut to length)

Misc Bolt Hardware & Matching T-nuts

Print Settings

• Printer:

Pulse XE

• Rafts:

Doesn't Matter

• Supports:

No

• Resolution:

0.30

• Infill:

35

• Filament brand:

MatterHackers

• Filament color:

Black

• Filament material:

CarbonFiber Nylon / PETG

• Notes:

These can be printed in any suitable material such as PETG, ABS, PC, Nylon.

This is by far, more reliable than the current dual z-motor setups. Cheaper to manufacture and does not limit your Z-axis height. With taller upper brackets and longer T8 screws, you could very possibly lift the hotend up to the bottom of the D frame. I am working on new brackets to gain 25-50mm higher Z.

Special Thank You to Grifter242 and the rest of my team for their amazing 3D work.