# Why do I have to lower my Z axis steps per mm?

First, X and Y axis works perfectly, I measured well. I have plugged all jumpers, and use a very standard ramps 1.4 setup with standard Nema 17 200rev 1.8 motors and A4988 drivers.

For Z axis, I have leadscrew with 8mm diameter and 2mm pitch.

I calculated it should be 1600 steps per mm. Problem is when I call G1 Z5 it goes to 2 cm. So I lowered my setting to 400 steps per mm and problem solved.

I don't understand what I'm missing here. I have used this calculator to find 1600.

Where I'm wrong on the math then?

• You are just amazing! I feel real guilty just reading 2mm pitch in the product description and verifying by looking at the lead teeth. Indeed, product title says 8mm screw pitch. TIL nut matters! Thank you! – morevitamins Jun 17 '17 at 20:57