Z table won’t calibrate

[Lee Anderton]

I’m struggling to get my Z axis to calibrate not matter what settings I try and use. My current set up is shown in the pictures and I’m using a step count of 15 in the settings. The motor jogs the table up and down absolutely fine but for 10mm visual movement up or down the controller shows in the region of 300. When I try and enter those details in the step count goes to 0.0xxxxx. The table won’t then move up or down. I’m thinking that my lifting screw rods are too fine and the Ruida controller can’t handle such a large discrepancy between motor shaft movement and table movement. Anybody got any ideas if my theory is correct? X and Y calibrate absolutely fine. I wouldn’t be too bothered but I want to set up auto focus with real numbers rather than entering 300 as an offset to get 10mm actual.