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 the taper of the tapered thread is 1:16, one side is 1:32, length means: positioning point plus effective length, for example, if I position 3.0 and effective length is 12.0, R = 1/32 X (3+12) = 0.46875
1. Sealed Pipe Thread (R)
Basic dimensions and tolerances of British sealed pipe threads
Fit types
There are two fit types for British sealed pipe threads: cylindrical internal thread with tapered external thread forms a "parallel/taper" fit; tapered internal thread with tapered external thread forms a "taper/taper" fit.
European countries mainly use "parallel/taper" fit threads; while countries outside Europe mainly use "parallel/taper" fit threads. There are some differences in the inspection gauges for the two types of threads; the current ISO standard for British sealed pipe thread gauges (ISO 7-2:2000) is designed based on the "parallel/taper" fit system.
The complete designation of British sealed pipe threads consists of the thread feature code, thread size code, and hand code. The feature code for British sealed cylindrical internal thread is: RP;
The feature code for British sealed tapered internal thread is: RC;
The feature code for British sealed tapered external thread is: R1 (for use with British sealed cylindrical internal thread); R2 (for use with British sealed tapered internal thread);
The hand code for left-hand thread is LH; the hand code for right-hand thread is omitted.
For sealed pipe threads, use RP/R1 and RC/R2 to represent "parallel/taper" and "taper/taper" thread pairs respectively.
2. Non-sealed Pipe Thread Basic dimensions and limit deviations of British non-sealed pipe threads
Marking:
The complete designation of British non-sealed pipe threads consists of the thread feature code, thread size code, pitch diameter tolerance grade code, and hand code
The feature code for British non-sealed cylindrical thread is: G
For British non-sealed cylindrical internal thread, the pitch diameter tolerance grade code is omitted; while for British non-sealed cylindrical external thread, the pitch diameter tolerance grade codes are A and B respectively
The hand code for left-hand thread is LH; the hand code for right-hand thread is omitted
When indicating a thread pair of British non-sealed pipe threads, only the marking code of the external thread is marked
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 thread pair: G2A
The tool for machining internal threads is pipe thread tap
The tool for machining external threads is die.
Others:
Conversion of 55° tapered pipe threads
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