Seaward Princess 2283 parts?

[sneuman]

I'm looking for the small brass orifice that goes in this cooktop to convert it from CNG to LP. I have a replacement regulator for propane and the old orifices (size for CNG), but can't for the life of me figure out the thread size on them -- none of the SAE taps/dies I have seem to be quite right. It may be metric, but it's fairly old and made in USA, so assuming it's not.

[sneuman]

found! Sure Marine: https://www.suremarineservice.com/