ASME B18.2.5M:2009 pdf free download

ASME B18.2.5M:2009 pdf free download.Metric 12-Point Flange Screws.
ASME B18.2.5M covers the complete dimensional and general data for metric series 12-point flange screws recognized as American National Standard. The inclusion of dimensional data in this Standard is not intended top1 that all products described are stock production items.
2 COMPARISONS WITH ISO STANDARDS
Letter symbols designating dimensional cha racteristics are in accord with ISO 225, except where capital letters have been used instead of lowercase letters in the ISO standards.
3 REFERENCED STANDARDS
The following is a list of publications referenced in this Standard, Unless otherwise specified, the standard(s) referenced shall be the most recent issue at the time of order placement.
ASME B1,3M, Screw Thread Caging Systems for Dimensional Acceptability — Inch and Metric Threads (UN, UNR, UN), M, and MJ)
ASME B1.13M, Metric Screw Threads — M Profile
ASME B18.2.8, Clearance Holes for Bolts, Screws, and Studs
ASME B18.2.9, Straightness Cage and Gaging for Bolts and Screws
ASME B18.12, Glossary of Terms for Mechanical Fasteners
ASME B18.18.1 M, Inspection and Quality Assurance for General Purpose Fasteners
ASME B18.18.2M, Inspection and Quality Assurance for High-Volume Machine Assembly Fasteners
19 THREAD LENGTH
The length of thread on screws is controlled by the maximum grip length, Lg maximum, and the minimum body length, L, minimum, as set forth in paras. 19.1 through 19.4.
19.1 Grip Length. L,
The grip length, L, is the distance, measured parallel to the axis of the screw, from the plane of the bearing circle diameter to the face of a noncounterbored, non- countersunk GO thread ring gage assembled by hand as far as the thread will permit. For standard diameter length combinations of screws, the values for L maximum are specified in Table 9. For diameter—length combinations not listed in Table 9, the maximum grip length for long screws that are not threaded full length is equal to the nominal screw length, L, minus the reference thread length, B, as specified in Table 10:
L maximum = L nominal — B
For short sereies of nominal lengths, L, that re shorter than the lengths specified in Table 10 for screws threaded full length,
L maximum = A maximum
as specified in Table 10.
19.2 Body Length, L5
Body length, L, on long screws that are not threaded full length is the distance, parallel to the axis of the screw, from the plane of the bearing circle to the last scratch of thread or top of the extrusion angle, whichever is closer to the head. For standard diameter-length combinations of screws, the values for L% minimum are specified in Table 9. For diameter—length combinations not listed in Table 9, the minimum body length on screws that are not threaded full length is equal to the maximum grip length, as determined above, minus the transition thread length, X, as specified in Table 10:
L. minimum = L. maximum — X
19.3 Thread Length, B
The thread length, B, specified in Table 10, is a reference dimension intended for calculation purposes onl’ and is the distance, parallel to the axis of the screw, from the extreme end of the screw to the last complete (full-form) thread.
19.4 TransitIon Thread Length, X
The transition thread length, X, specified in Table 10, is a reference dimension intended for calculation purposes only. It includes the length of incomplete threads and tolerances on grip length and body length.