All, Purchased a cool little winged brass gas cap for my speedster project and I'm completely stumped by the threads on this thing... The cap has male threads, 16 per inch, threads measure approx. 2.03" O.D. I am 100% sure it is not 2" NPT...won't fit the 2" NPT threads on my fuel tank. Would love to adapt this to a filler tube, but need to know what these threads are.
Wow, a thread thread! (Sorry, couldn't resist) That appears to be a straight thread, not tapered like NPT (National Pipe Tapered). You should be be to get a thread gauge at a good hardware store in order to get the pitch. Maybe a machinist HAMBer can help out, or check the Starrett website.
Pitch is 16 TPI...I just can't find a reference for a 2.03 (2 1/32) x 16 thread size anywhere...comes close to a fine metric thread (M52 x 1.5) but a 1.5mm pitch is 16.9 TPI.
Any idea what it's off? That can often lead you in the right direction. I don't have my Machinery Handbook here but I'm sure someone on here has one on them.
Adapting it to a filler tube would be a no brainer for a good machinist. He would just measure and make the female for that to fit. Even if it isn't a standard diameter as long as he can measure thread pitch and depth with diameter it can easily be done.
Blue One, That's what I was hoping to hear. I'll run it by the local machine shop & see what they say. Thanks!
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