Abstract： ASME B16.4:2011 pdf download.Gray lron Threaded Fittings Classes 125 and 250. 7 DIMENSIONS AND TOLERANCES (a) Center-to-end dimensions in millimeters are given for standard straight and reducing fittings in Tables 2 through 6 (Tables 1-2 th...

ASME B16.4:2011 pdf download.Gray lron Threaded Fittings Classes 125 and 250.

7 DIMENSIONS AND TOLERANCES

(a) Center-to-end dimensions in millimeters are given for standard straight and reducing fittings in Tables 2

through 6 (Tables 1-2 through 1-6 are in U.S. Customary units). The sketches of fittings shown in the Standard are representative and for the purpose of illustration.

(b) The dimensions in Tables 2 through 6 (Tables 1-2 through 1-6) of reducing fittings are For use only when

making patterns for the specific reducing fitting in question and do not apply when a larger size pattern is

bushed to make the reducing fitting wanted.

(c) The following tolerances shall be permitted:

(1) Metal Thickness Tokrances. Metal thickness at no point in the castings shall be less than 90% of the value

given in Tables 2 through 6 (Tables 1-2 through 1-6).

(2) Center-to-End Thlera ,,ces. T’ermi tt ed tolerances on the center-to-end dimensions of the fittings are shown in Tables 7 and 1-7. Tolerances for end-to-end dimensions and lengths of couplings and reducers shall be twice

those given. The largest opening in a reducing fitting governs the tolerances to he applied to all openings. These tolerances do not apply to return bends and caps.

8 THREADING

(a) All fittings shall be threaded according to ANSL/ASME B1.20.1, and the variations in threading shall be

limited to one turn large or one turn small from the gaging notch on the plug when using working gages.

(b) The reference point for gaging internal fittings threads depends upon the chamfer diameter.

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