ASME B1.30:2002 pdf free download

ASME B1.30:2002 pdf free download.SCREW THREADS: STANDARD PRACTICE FOR CALCULTING AND ROUNDING DIMENSIONS.
(a) Minor Diameter Exceptions fur Internal Threads:
(1) Minimum Minor Diameter. All classes are calculated and then rounded off to the nearest 0.001 in. and expressed in three decimal places for sizes 0.138 in. and larger. For Class 3B, a zero is added to yield four decimal places.
(2) Maximum Minor Diameter. Al] classes are calculated before rounding. then rounded for Classes lB and 2B to the nearest 0.001 in. for sizes 0.138 in. and larger. Class 3B values are rounded to four decimal places.
3.1.4 Metric screw threads are dimensioned in millimeters. The final values of pitch diameter, ma)or diameter, minor diameter, allowance and thread element tolerances are expressed to three decimal places.
3.1.5 Values containing multiple trailing zeros out to the required number of decimal places can be expressed by displaying only two of them beyond the last significant digit.
EXAMPLE 20 threads per inch has a pitch equal to 005&)00O0 and can be expressed as 0.0500.
3.2 Examples
The formulas in the examples for inch screw threads in Tables 2.3.4 and 5 are based on those listed in ASME B1.1, Unified Inch Screw Threads. Tables 2 and 3 are based on a size that when converted from a fraction to a decimal will result in a number that has only four decimal places. Tables 4 and 5 are based on a size that when converted will result in a number with infinite numbers of digits after the decimal point.
The formulas in the examples for metric screw threads in Tables 6,7, and 9 are based on those listed in ASME B1.13M, Metric Screw Threads. Tables 6 and 7 show the use of the tabulated values for allowances and tolerances (in accordance with ISO 965-1) for the cakulation of size limits for standard diameter/pitch combinations listed in both 150 261 and ASME Hl.13M. The constant values differ from those used for inch screw threads, in accordance with the policy of rounding of this Standard, because metric limits of size are expressed to only three decimal places rather than four.