My sizes are out

[JAZZCNC]

In the manual there's "Level of Axis pulse signal" what does this mean? Is that the rising/falling edge?

This will be the pulse timing and I wouldn't mess with it if your not missing steps or losing position.

The fact your parts are the wrong size will be down to either a mechanical issue or simply because the pitch doesn't correspond to the steps per setting. The best way is to command a move and accurately measure the distance it moved. And when I say accurately then a tape measure or even a steel rule isn't accurate enough. For instance, I use linear scales with a DRO to compare actual distanced moved to the commanded. I then adjust the steps per until they match.

The longer the move the better but if you have lets say 150mm length set of digital vernier gauges these can get you very close to perfect.

Edit: One other thing, if these are cheap Chinese screws the pitch can vary along it's length so it's worth taking readings in a few places. Likewise, if you have been using the machine already and cutting in the same spot all the time then there will be wear in this location compared to the unused or less used regions. This is why it's a good idea to move around the bed when cutting small parts rather always at the easiest place to reach.1