ASME B18.2.3.9M:2001 pdf download

ASME B18.2.3.9M:2001 pdf download.METRIC HEAVY HEX FLANGE SCREWS
1 SCOPE
(a) This Standard covers the complete dimensional and general data for metric series heavy hex flange screws recognized as American National Standard. (b) The inclusion ofdimensional data in this Standard is not intended to imply that all products described are stock production items. Consumers should consult with suppliers concerning availability of products.
2 COMPARISON WITH ISO/DIS 8102
(a) Heavy hex flange screws as presented in this standard are harmonized to the extent possible with the draft international standard ISO/DIS 8102, Hexagon Bolts With Flange—Heavy Series, and with revisions agreed to by ISO/TC2/WG2 in May 1989 in Zurich and later that have not been published in a revised draft. If it were published, the dimensional differences between this Standard and ISO/DIS 8102 would be few, relatively minor, and none would affect functional interchangeability ofscrews manufactured to the require- ments of either. This Standard specifies some requirements that are not included in ISO/DIS 8102. Dimensional requirements shown in bold type are in addition to, or differ from, ISO/DIS 8102. The technical differences between this standard and the ISO documents are described in Appendix A. (b) Letter symbols designating dimensional charac- teristics are in accord with ISO 225, Fasteners—Bolts, Screws, Studs and Nuts—Symbols and Designations of Dimensions, and with ISO/DIS 8102, except where capitals have been used instead of lowercase letters used in the ISO standards.
6 TOP OF HEAD
The top of head shall be either full form or indented at manufacturer’s option, and shall be either chamfered or rounded. The diameter of the chamfer circle or start of rounding shall be equal to the maximum width across flats, S maximum, within a tolerance of −15%. If the top of the head is indented, the periphery may be rounded.
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 para. 22.
8 WRENCHING HEIGHT
The wrenching height, K w , is the distance at a corner of the hexagon from the junction of hex head with the flange to the last plane of full-formed hexagon (i.e., the plane closest to the top of the head at which the width across corners, E, of the hexagon is within its specified limits).
10 GAGING OF HEAVY HEX FLANGE HEAD
See Table 1. 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.
11 POSITION OF HEAD
At maximum material condition, the axis of the hexagon of the head shall be within a positional toler- ance zone of the diameter specified in Table 2 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 0.5D from the head, and shall be either wholly plain body or wholly the thread pitch diameter, not including the thread runout or the underhead fillet.
12 FLANGE
The top surface of the flange shall be conical or slightly rounded (convex). Radius, R 2 , applies both at the corners and at the flats of the hexagon. The contour of edge at flange periphery, between the maximum flange diameter, D c maximum, and the minimum bearing circle diameter, D w minimum, shall be optional provided that the minimum flange edge thickness, C minimum, is maintained at the minimum bearing circle diameter, D w minimum.