what is the M148 pitch?
3 Answers

I found a M150 thread in my Machinist Handbook, but it's for a Trapezoidal Metric Thread. The pitch is 16mm (distance between threads)

The rotors for a screw compressor are not based on standard threads. Designing this type of equipment is a specialized task, so to produce good working machines, knowledge and experience is needed, that is why if you need one you purchase it from a manufacturer who produces these machines. If you desire to learn a bit about screw compressors for yourself, the first step is to get an understanding of how they work. I did a quick google search, " design screw compressor " and came up with plenty of links to start with. This one, a company local to me https://www.compair.com/en-nz/technologies/screw-compressor is where I would start if a project I was working on required a screw compressor. There is no way to design any part of, or complete machine without at least knowing how it works.
The pitch most probably is calculated from the machines specification, such as rate and pressure the compressor will supply, the power required and the speed the rotors will run at. Just looking at the basic specs for a screw compressor, designing one that will work properly is not a simple task. A working one requires way more than a guessed design flashy CAD model.

I think this site can be helpfull for you
https://www.engineersedge.com/hardware/metric-external-thread-sizes6.htm