Clamp Position to transition to turn object completely visible or not.

Hi.

I built a shader that use a Position node to make a transition’s shader.
Working fine but the problem is that I can’t clamp the value to 0-1 from totaly invisible and totaly visible.

In my Position node I am using Object mode > Split, in my case using the R channel and piped in the In Step channel. Simple, there are many examples online. But in the Edge Step channel, I want to use a slider clampped between 0-1 but to really to make what I want I need to use values like -5.18 to -3.5…Ok, I can insert manually this values and clamp after but I have many object with diferent sizes and I will need to do manually for everyone.

Is possible to get this by shader?

thank you.

Probably is something with my model…Because if I use in a sphere for example, is easy to clamp bacausae the size of the model doesnt matter.