Magnum intake drilling plate project

Jadaharabi said
I'm not confused about anything. As I said the pipe nipple is not NPT it is MIP.

MIP stands for Male Iron Pipe, or some would say Male International Pipe. The same pipe size can also be called MPT, for Male Pipe Thread. FIP means Female Iron (or International) Pipe and can also be called FPT for Female Pipe Thread. To add confusion, there is NPT, which stands for National Pipe Thread.

According to what I know MIP is just another nickname for "murican pipe" so again I ask, "what is the difference?"

https://www.freshwatersystems.com/blogs/blog/how-to-determine-pipe-thread-type-and-pipe

Common pipe thread types:

NPT or NPS (national pipe tapered or straight): Most common in North America
MIP or FIP (male or female iron pipe): Same thread dimensions as NPT
BSP(T) or BSP(S) (British standard pipe tapered or straight): Most common in Europe
Compression: A unique threaded fitting that does not mate with other thread types
UNS (National Unified Special): Some compatible with compression fittings

So again? what exactly is the difference? Is this smaller ID pipe, or differnt thread or what? Some fittings are threaded "straight' which might appear different but is still a variation of NPT