In the mood for a headache?

[Shopgeezer]

In my quest for boiler fittings I happened across the PM Engineering description of the various threads they sell for model steam engine use. Ay Chihuahua! I am a bit confused. Have a look:

https://www.pmmodelengines.com/model-pipe-threads/

I think I will just go to Home Depot and use whatever bushings they have on the shelf.