ASME B18.2.1-2010 pdf download
ASME B18.2.1-2010 pdf download.Square, Hex,HeavyHex, and Askew Head Bolts and Hex, HeavyHex,Hex Flange, Lobed Head, and Lag Screws (Inch Series).
4.7 Thread Length
The length of thread on screws shall be controlled by the grip gaging length, LG, max., and body length, LB, mm.
For short screws threaded full length, LG, max. and LB, mm. are given in Table 11 (see Fig. 3). Long screws not threaded full length of diameters through 1’/2 in. and lengths through 12 in. LG, max. and LB. mm. are specified in Table 12.
For diameter-length combinations not included in Table 11 or 12, the maximum grip gaging length, LG, max., for long screws that are not threaded full length, as calculated and rounded to two decimal places, shall be equal to the nominal screw length minus the nominal thread length (La, max. = L, nom. — LT). It shall be used as the criterion for inspection.
Nominal thread length, LT, is a reference dimension intended for calculation purposes only, which represents the distance from the extreme end of the screw to the last complete (full form) thread. Nominal thread length equals twice the basic thread diameter plus 0.25 in. for nominal screw length up to and including 6 in. and twice the basic thread diameter plus 0.50 in. for nominal lengths over 6 in.
Body length, LB, mm., is the distance measured parallel to the axis of screw from the underhead bearing surface to the last scratch of thread or to the top of the extrusion angle. For diameter length combinations not included in Table 11 or 12, the minimum body length, L8, mm., as calculated and rounded to two decimal places, shall he equal to the maximum grip gaging length minus the maximum transition thread length (LB. mm. = LG, max. — Y). It shall be a criterion for inspection.
Transition thread length, Y, is a reference dimension equal to five coarse (UNC) pitches and intended for calculation purposes only. It includes the length of incomplete threads, the extrusion angle on rolled threads, and tolerances on grip length.
4.8 Length Tolerances
Screw length tolerances are given in Table 13.
4.9 Material
Unless otherwise specified, chemical and mechanical properties of steel screws shall conform to ASTM A 449, ASTM A 354, or SAE J429. Stainless steel screws shall conform to the requirements of ASTM F 593. Nonferrous screws shall conform to the requirements of ASTM F 468.
