From k8xxx-3dprinter
When not warped, the stock leadscrew does it's job but is a little jiggly and makes awful noises on longer moves.
You might want a more precise system and a trapezoidal spindle is what you need.
Replacing the stock screw with a trapezoidal one will increase the precision and the smoothness of the movement but still leaves the arm supporting the extruder free to sag a bit on the other side. It means that the arm isn't level and the layer thickness will vary a bit from side to side.
- With this mod you can install one or two trapezoidal spindles. Some mods use a second stepper motor to drive the second screw but if one of the motors fails it can end up destroying the whole Z assembly. The selected system here is driving the second rod with a closed timing belt set between the two spindles.
- Two spindle diameters can be used : 8 and 10 mm, the latter being more sturdy and less prone to bending.
- The original design was made by donboy with 8 mm spindles.
8mm dual trapezoidal spindle
- Link to the project on Thingiverse
10mm dual trapezoidal spindle
- This is the same design adapted to a 10x2 mm spindle. The horizontal upper bar is set at the top of the frame with the angle brackets fitted to the under side. That way you can gain a good 2 cm in height for the Z-axis.
- Link to the project on Thingiverse