1、 WORLDWIDE ENGINEERING STANDARDS General Specification GMW3362 M Point for External Metric Thread, Coarse Pitch Fasteners Copyright 2013 General Motors Company All Rights Reserved March 2013 Page 1 of 3 1 Introduction 1.1 Scope. This standard specifies the characteristics of M Points for external me
2、tric threaded fasteners with coarse pitch M5, M6, M8, M10, M12, M14 and M16. The point is added to the specified nominal length of the fastener. 1.2 Designation. Not applicable. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Sp
3、ecifications. None 2.2 GM Standards/Specifications. GMW3059 3 Requirements 3.1 Dimensions. All dimensions in this standard are given in millimeters (mm) unless otherwise stated. 3.1.1 Nominal Length. For fasteners of nominal length up to and including 50 mm, the tolerance shall be 0.15 mm. For faste
4、ners of nominal length over 50 mm, the tolerance shall be 0.25 mm. The nominal length is the distance parallel to the fastener axis from the bearing surface to the lead thread where the thread profile first exceeds 0.20 times the thread pitch in height (measured from the thread root). 3.1.2 M Point
5、Thread. The M Point thread length, u, is a reference dimension used for calculation purposes. The profile of all lead threads shall not exceed maximum material condition boundaries of the standard thread. At least one complete turn (360 degrees) of the first two threads shall be smoothly and uniform
6、ly curved for its entire profile with no localized scallops, fissures, underfill, flats, or other discontinuities permitted at the crest of the thread. A thread specific GO gage shall pass freely over first four threads after coating. 3.1.3 Dog Point. The dog point length, z3, is a minimum length fo
7、r the dog point cylinder. The length of the dog point cylinder shall be measured from the point on the lead thread where the lead thread first exceeds 0.20 times the thread pitch in height (measured from the thread root) to the point on the cylinder where the end radius is tangent. The diameter of t
8、he dog point cylinder, dx, shall be larger than dx minimum when measured at the tangent point. Dog point cylinder diameter dx shall be held for entire dog point length z3 with no taper allowed. 3.1.4 Radius Point. The radius point length, z5, is a minimum length for the point beyond the dog point. T
9、he radius of this point, r, is a reference dimension only, and its shape may not be a true radius after threading. The end of the point shall be reasonably square with the thread axis, and the edge may be irregular. The tip diameter, dy, is a maximum for the radius point. 3.1.5 Point Length. The ove
10、rall point length, z4, is a maximum length. It represents the sum of the dog point length and the radius point length. 3.1.6 Minimum Thread Length. The minimum full thread length measured from the bearing surface is the minimum nominal length (minimum) minus the M Point thread length. 3.1.7 Maximum
11、Overall Length. The maximum overall (built-in) length is the sum of the maximum nominal length (maximum) and the maximum overall point length (z4 maximum). It is the maximum distance from the bearing surface to the end of the fastener. Copyright General Motors Company Provided by IHS under license w
12、ith General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW3362 Copyright 2013 General Motors Company All Rights Reserved March 2013 Page 2 of 3 Note 1: (2.5 pitches typical) Figure 1: Dimension Illustration Tabl
13、e 1: Dimensions Note 1 Thread M5 M6 M8 M10 M12 M14 M16 dx maximum minimum 4.03 3.95 4.80 4.72 6.54 6.45 8.23 8.14 9.95 9.88 11.72 11.60 13.72 13.60 dy maximum 3.40 4.00 5.50 6.80 8.20 9.60 10.90 r reference 1.5 1.8 2.3 2.8 3.3 4.1 4.7 u reference 1.8 2.3 2.8 3.4 4.0 4.5 4.5 z3 minimum 1.30 1.50 2.10
14、 2.60 3.15 3.68 4.10 z4 maximum 2.50 2.85 3.90 4.65 5.65 6.43 7.10 z5 minimum 0.60 0.75 1.00 1.25 1.50 1.75 2.00 Note 1: All dimensions are in millimeters. 3.2 Material. Not applicable. 3.3 Surface Treatment. Not applicable. 3.4 Thread. Not applicable. 3.5 Tolerances. Not applicable. 3.6 Surface Dis
15、continuities. Not applicable. 3.7 Proof Load Requirements. Not applicable. 3.8 Acceptability. Not applicable. 4 Rules and Regulations 4.1 Legal Regulations. All materials must satisfy applicable laws, rules, regulations and recommendations valid in the country of usage. 4.2 Language. In the event of
16、 conflict between the English and domestic language, the English language shall take precedence. 4.3 Inspection and Rejection. Samples of components or materials released to a GM general specification shall be tested for conformity with the requirements of this general specification and approved by
17、the responsible Engineering department prior to commencement of delivery of bulk supplies. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS G
18、MW3362 Copyright 2013 General Motors Company All Rights Reserved March 2013 Page 3 of 3 A new approval must be received for any changes, e.g., properties, manufacturing process, location of manufacture, etc. If not otherwise agreed, all testing and documentation normally required for initial release
19、 must be completed. It is the responsibility of the supplier to inform the customer in a timely manner, without solicitation, and to include documentation of all modifications of materials and/or processes and to apply for a new release. If not otherwise agreed, all release tests shall be repeated a
20、nd documented by the supplier prior to commencement of delivery of non-conforming bulk supplies. In individual cases, a shorter test can be agreed to between the responsible Engineering department and the supplier. 4.4 Initial Source Approval. No shipments shall be made by any supplier until represe
21、ntative initial production samples have been approved by the appropriate Materials Engineering department(s) as meeting the requirements of this specification. 4.5 All materials supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 5
22、Notes 5.1 Glossary. Not applicable. 5.2 Acronyms, Abbreviations, and Symbols. SSLT Subsystem Leadership Team 6 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: GMW3362 7 Release and Revisions This standard was originated in October 1999. It was first ap
23、proved in February 2000. It was first published in June 2000. Issue Publication Date Description (Organization) 1 JUN 2000 Initial publication. 2 JUN 2001 Editorial Revision. (GMNA) 3 MAY 2005 Reformatted, 3.1 added, Table 1. (Fasteners Group) 4 MAY 2008 Revise minimum Dx dimensions in Table 1. (Glo
24、bal Fastening SSLT) 5 MAR 2013 Five year refresh of standard. No technical changes - updated to 2013 template. (Global Fastening Engineering) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
