ASME B18.2.3.3M:2007 pdf free download.Metric Heavy Hex Screws.
1.1.1 ASME B18.2.3.3M covers the complete general and dimensional data for metric heavy hex screws recognized as American National Standard.
1.1.2 The inclusion of dimensional data in this Standard is not intended to imply that all of the sizes in conjunction with the various options described herein are stock items. Consumers should consult with suppliers concerning lists of stock production sizes.
1.2 ComparIson With ISO Standards
1.2.1 ISO has not yet initiated development of an ISO standard for heavy hex screws. However, nominal diameters and thread pitches, body diameters, widths across flats, bearing surface diameters, head heights. thread lengths, thread dimensions, and nominal lengths are in accord with ISO standards for related hex head screws and bolts.
1.22 Letter symbols designating dimensional characteristics are in accord with those used in ISO standards, except capital letters have been used instead of the lowercase letters used in ISO standards.
1.3 Terminology
For definitions of terms relating to fasteners or component features thereof used in this Standard, refer to
ASME 818.12.
1.4 Dimensions
1.4.1 All dimensions in this Standard are in millimeters, unless stated otherwise.
1.42 Symbols specifying geometric characteristics are in accord with ASME Y14,5M.
1.5 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 Gaging Systems for Dimensional Acceptability — Inch and Metric Screw Threads ASME Bl.13M, Metric Screw Threads — M Profile
2.6.4 Thread length, B, as specified in Table 7 is a reference dimension intended for calculation purposes only, and is the distance measured parallel to the axis of the screi from the extreme end of the screw to the last complete (full form) thread.
2.6.5 Transition thread length, X, as specified in Table 7 is a reference dimension intended for calculation purposes only. It includes the length of incomplete threads and tolerances on grip gaging length and body length. The transition from full thread to incomplete thread shall be smooth and uniform. The major diameter of the incomplete threads shall not exceed the actual major diameter of the complete (full form) threads. For screws of property class 10.9 and higher strength materials (tensile strength 1040 MPa and higher), the transition threads shall have a rounded root contour, no radius of which shall be less than the specified minimum radius at the root of the full-form thread.
2.7 Position of Body-to-Thread
For products with cut threads at maximum material condition, the axis of the screw bod D, over a length equal to the nominal screw diameter from the last scratch of thread, shall be within the positional zone diameter specified in Table I, with respect to the axis of the thread, over a length equal to the nominal screw diameter from the last complete thread. A gage and gaging procedure for checking body position is given in Nonmandatory Appendix B.
2.8 Screw Threads
2.8.1 Thread Series and Tolerance Class. Threads shall be metric coarse thread series conforming to dimensions for general purpose external threads given in ASME Bl.13M, unless otherwise specified by the pur. chaser. The Class 6g tolerance shall apply to plain finish (unplated or uncoated) screws, and to plated or coatedscrews before plating or coating. For plated or coatedscrew threads, Class 6h tolerance high limit (GO) andClass 6g tolerance low limit (NOT GO) shall apply.
2.8.2 Thread Gaging. Unless otherwise specified,dimensional acceptability of screw threads shall bebased on System 21 of ASME B1.3M.
2.9 Material and Mechanical Properties
2.9.1 Carbon and Alloy Steel. Materials and prop-erty class shall conform to ASTM F 568M.
2.9.2 Corrosion-Resistant Steels.Unless otherwisespecified, corrosion-resistant screws shall conform to therequirements of ASTM F 738M.
2.9.3 Nonferrous Metals.Unless otherwise speci-fied,nonferrous screws shall conform to the require-ments of ASTM F 468M.
