ASME B16.22-2012 pdf – Wrought Copper and Copper Alloy Solder-Joint Pressure Fittings.
The largest opening in the fitting shall govern the tolerance to be applied to all openings.
9.3 Ovallty of Fitting End (C or FTG)
Maximum ovality of the fitting solder-point end shall not exceed 1% of the mavcimum diameters shown in Table I (Table LI-I). The average of the maximum and minimum diameters shall he within the dimensions shown in the Table.
9.4 Inside Diameter of Riling
1 he minimum cross-sectional area of the inside diameter through the fitting body shall not be lvss than the theoretical minimum area defined b diameter 0 in Table 1 (Table Il-I). The out-of-roundness condition ol the cross-sectional area shall not exceed the value shown in Table I (Table lI-I).
For reducer or adapter fittings, the smallest end dianieter shall appI provided that this diameter does not restrict the other outlets.
9.5 Wall Thickness
The minimum wall thickness shall not he less than that shown in Table I (Table Il-I).
Fitting threads shall be right-hand, conforming to ASME 131.20.1. The shall be taper threads (NI’T).
10.1 Countersink o Chamfer
All internal threads shall be countersunk a distance no less than one-half the pitch of the thread, at an angle of approximately 45 deg with the axis of the thread. All external threads shall be chamfered at an angle of 30 deg to 45 deg from the axis. Countersinking and chamfering shall be concentric with the threads.
The length of threads shall be measured to include the countersink or chamfer.
10.2 Threading Tolerances
Tapered pipe threads (Nl shall he checked by use of plug or ring gages in either standard or limit types. When gaging internal taper threads, the plug gage shall be screwed hand-tight into the fitting. The reference point for gaging internal product threads dependson the chamfer diameter. When the internal chamfer diameter exceeds the major diameter of the internal thread, the reference point shall be the last thread scratch on the chamfer cone. Otherwise, when the internal diamfer diameter does not exceed the major diameter of the internal thread, the reference point shall Lw the end of the fitting. In gaging external taper threads, the ring gage shall be screwed hand-tight on the external thread. On the external thread, the ring gage shall be flush with the end of the thread.
Tolerance for an intenal threaded end having an oilernal shoulder shall he from the gage reference point (notch) to one turn small. Tolerance for an internally threaded end without a shoulder and fur an externally threaded end, shall be from one turn small to one turn large.
10.3 DesIgn of Threaded Ends
The wrenching section of internally threaded ends shall be polygonal, and the wrenching section of externally threaded ends shall be furnished with either polygon or flats, at the manufacturer’s option.
The maximum allowable deviation In the angular alignment of any end from the specified axis position shall be deg (1 deg total). See Fig. 3.
12.1 Preferred Gaging Method of Solder-foint Ends
The preferred method of gaging the diameter tolerances for external and internal ends shall be by the use of plain plug and ring gages designed to hold the product within the limits established in Table 1 (Table Il-I). Gage tolerances shall LwCbss ZM. as defined in ASME B4.4M.
122 OptIonal Gaging Method of Sotder.Jolnt Ends
For gaging the diameter tolerance of external and internal ends, the use of direct reading instruments instead 04 ring and plug gages as specified in para. 12.1 shall be permitted. When gaging the diameters of external and internal ends using direct reading instru ments, refer to para. 9.3.
12.3 Standard Gaging Method of Threaded Ends
The standard method of gaging the externally and inlernally threaded ends shall be in accordance with the requirements of ASME 131.20.1.
NOTE in gaging p11w thread,i, it is acceptable and csnmnn practice in rap oe tap the part to ensure prnpre seating cif the gage. However. it is necessary to clean both the gage and product threads to ensure that they are free of chips. burrs, abrasives.malenals.