ASME B18.2.5M-2009 pdf free

ASME B18.2.5M-2009 pdf free.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 to imply that all products described are stock production items.
2 COMPARISONS WITH ISO STANDARDS
Letter symbols designating dimensional characteristics 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.
4 TERMINOLOGY
For definitions of terms relating to fasteners or features thereof used in this Standard, refer to ASME B18.12.
5 DIMENSIONS
(a) All dimensions in this Standard are given in millimeters (mm), and apply before any coating, unless stated otherwise.
(b) Symbols specifying geometric characteristics are in accordance with ASME Y14.5.
6 TOP OF HEAD
The top of head shall be chamfered or rounded with diameter of chamfer circle or start of rounding being equal to maximum width across flats within a tolerance of —15% of maximum width across flats.
7 HEAD HEIGHT
The head height, K, is the distance, parallel to the axis of the screw, from the plane of the bearing circle to the top of the head, not including any raised markings (see section 21).
8 WRENCHING HEIGHT
Corners of the 12 points shall be fully formed and reasonably uniform over the wrenching height, Ku.. Head drive root radius, R4, applies to the entire length of the wrenching height, K (see Table 1).
9 GAGING OF 12-POINT FLANGE HEAD
The head shall be gaged using two ring gages, A and B, to demonstrate the coincidental acceptability of wrenching height, corner fill, and width across corners. Gage A shall be placed over the head and shall seat on the flange. Gage B shall be placed on the top of the head normal to the screw axis. The two gages shall not be in contact (see Table 2).
10 POSITION OF HEAD
At maximum material condition, the axis of the 12 points of the head shall be within a positional tolerance zone of the diameter specified in Table 3 with respect to the axis of the shank over a distance under the head equal to the nominal screw diameter, D. The datum shall be as close to the head as practicable, but within O.5D from the head, and shall be either wholly plain body or wholly the thread malor diameter, not including the thread runout or the underhead fillet.ASME B18.2.5M pdf download.