My calibration at my printer is okay. When I try to move 10 mm, it's exactly 10 mm.

But I want to know what is my precision for Z-axis.

(not posting the link of the product maybe it's not okay for the platform)

Spec for leadscrew:

  • Lead screw diameter: 8 mm
  • Screw pitch: 2 mm
  • Lead of thread: 8 mm

calculator page

My question; is my gear ratio 4:1 or 1:4? It's giving different results.

  • 1
    $\begingroup$ This answer gives insight in leadscrews. $\endgroup$
    – 0scar
    May 31, 2020 at 22:29
  • 1
    $\begingroup$ In my experience, with decent stepper drivers (e.g. A4988), sticking to full steps for Z axis does not seem to be important (doesn't seem to make any difference to print quality). $\endgroup$ Jun 1, 2020 at 3:11
  • $\begingroup$ My question is not just for 3D printers, I'm thinking about modifying to high precision CNC :) Thanks in advance $\endgroup$
    – ahmetertem
    Jun 1, 2020 at 3:14
  • 1
    $\begingroup$ In short: It's 1:1, and your "pitch" for that calculator is 8 mm. Pitch and lead are frequently confused. $\endgroup$
    – towe
    Jun 2, 2020 at 11:08

1 Answer 1


Your lead screw nut advances 8 mm every complete rotation of 200 full steps, so a single full step would change the height by 8/200 = 0.04 mm. This implies you need to set the layer height a multiple of 0.04 mm.

The gear ratio of 4:1 (a reduction) is required to get to your desired 0.01 mm layer height, but that is a very uncommon and a too small layer height to use.


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