RC2 inch tapered pipe thread, 11 threads per inch, pitch = 25.4/11 = 2.309, thread height (depth) = 2.309 × 0.64 = 1.479, taper is fixed at 1:16, R equals 1/32 times the length, 1/32 means that the taper of the tapered thread is 1:16, single side is 1:32, length means: positioning point plus effective length, for example, if I position 3.0, effective length is 12.0, R = 1/32 × (3+12) = 0.46875
1. Sealed Pipe Thread (R)
Basic dimensions and tolerances of British standard sealed pipe threads
Fitting methods
There are two fitting methods for British standard sealed pipe threads: cylindrical internal thread with tapered external thread forming a "cylindrical/tapered" fit; tapered internal thread with tapered external thread forming a "tapered/tapered" fit.
European countries mainly use "cylindrical/tapered" fit threads; while countries outside Europe mainly use "cylindrical/tapered" fit threads. There are some differences in the inspection gauges for the two types of threads; the current ISO standard for British standard sealed pipe thread gauges (ISO 7-2:2000) is designed according to the "cylindrical/tapered" fit system.
The complete marking of British standard sealed pipe threads consists of the thread feature code, thread size code, and rotation direction code. The feature code for British standard sealed cylindrical internal threads is: RP;
The feature code for British standard sealed tapered internal threads is: RC;
The feature code for British standard sealed tapered external threads is: R1 (used with British standard sealed cylindrical internal threads); R2 (used with British standard sealed tapered internal threads);
The rotation direction code for left-hand threads is LH; the rotation direction code for right-hand threads is omitted.
For sealed pipe threads, RP/R1 and RC/R2 are used to represent "cylindrical/tapered" and "tapered/tapered" thread pairs respectively.
2. Non-sealed Pipe Thread Basic dimensions and limit deviations of British standard non-sealed pipe threads
Marking:
The complete marking of British standard non-sealed pipe threads consists of the thread feature code, thread size code, pitch diameter tolerance grade code, and rotation direction code.
The feature code for British standard non-sealed cylindrical threads is: G
For British standard non-sealed cylindrical internal threads, the pitch diameter tolerance grade code is omitted; while the pitch diameter tolerance grade codes for British standard non-sealed cylindrical external threads are A and B respectively.
The rotation direction code for left-hand threads is LH; the rotation direction code for right-hand threads is omitted.
When representing a thread pair of British standard non-sealed pipe threads, only the marking code of the external thread is indicated.
Examples:
Size code 2, right-hand, non-sealed cylindrical internal thread: G2
Size code 3, grade A, right-hand, non-sealed cylindrical external thread: G3A
Size code 4, grade B, left-hand, non-sealed cylindrical external thread: G4B-LH
Size code 2, right-hand, non-sealed cylindrical internal thread with grade A cylindrical external thread forming a thread pair: G2A
The tool for machining internal threads is the pipe thread tap.
The tool for machining external threads is the die.
Others:
Conversion of 55° tapered pipe threads
