I have a drawing with OD thread ann

Question

I have a drawing with OD thread ann

vayager4 (Mechanical)

(OP)

18 Aug 21 00:28

I have a drawing with OD thread annotation M114 X 8TPI . We need to find out the pitch diameter. Looks like customized very long ago.
Could any one can help me to find the pitch diameter?
James

3DDave (Aerospace) · Answer 1 · 2021-08-18 02:26:06

Not going to be easy with identifying what the thread form is supposed to be. What does the mating part call for?

vayager4 (Mechanical) · Answer 2 · 2021-08-18 05:22:21

Mating part is hose tail nut, but we do not have one.

btrueblood (Mechanical) · Answer 3 · 2021-08-18 14:24:18

That is ridiculously close to the o.d. and tpi of an American 4"-8 NPSC (National Pipe Straight Coupling) pipe thread (4" pipe has a nominal o.d. of 4.5 inches, or roughly 114-115 mm). Suggest you get a copy of Machinery's Handbook and look at the various straight pipe threads (NPSM, NPSF and NPSI are other variations of straight (non tapered) pipe threads. For NPSC the pitch diameter range for 4"-8 is 4.3754 to 4.3988 inches.

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I have a drawing with OD thread ann