A/C Clutch replacement on a Caravan 3.3ltr

I have a Caravan with a 3.3 ltr eng. with a 6C17 A/C compressor 6-rib.

I cannot locate a Clutch Plate Remover tool for this compressor only one for a c171 with a 5/8" removal tool.

So I think I will make a clutch plate remove tool, but this compressor has a larger threaded area (where the clutch tool screws into) in the clutch plate then my other caravan 5/8"

What is the Size?

Is it metric or standard?

Thanks Will