1、This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 1 of 10 NAVISTAR, INC. Material, Parts, and Process Specifications
2、(MPAPS) NUMBER: MPAPS S-CM-1.101-GS/PL Former Designation: ESP-CM-1.101-GS TITLE: Machine Screws Metric Series CURRENT REV No.: 1506 DATE: June 2015 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: ESP-CM-1.101-GS - August 2009 PRINTED COPIES OF THIS DOCUMENT M
3、UST BE VERIFIED FOR CURRENT REVISION This specification may involve hazardous materials, equipment, and procedures. This specification does not purport to address all of the safety issues associated with its use. The user is responsible to consult appropriate safety and health practices and to deter
4、mine the applicability of regulatory limits prior to use. Change Notice: Changed to New MPAPS format; Combined GS, GI, PP. 1.0 GENERAL: These standards may differ in some respects with certain segments of ISO and national standards. In recognition of these differences, the sizes and tolerance ranges
5、 used were established in an effort to enable the use of commercially available items that are dimensionally interchangeable worldwide. For purposes of this standard, the generic term “machine screws“ has been adopted as applying to products normally threaded to the head in smaller nominal sizes and
6、 made of low carbon steel. This specification contains the essentials of the following standards: International Organization for Standardization: ISO 898/1, 965/2, 4757, 7045, 7046, 7047, 7721 British Standards Institute: BS 4183 German Institute of Standardization: DIN 965, 966, 7985 American Socie
7、ty of Mechanical Engineers: B18.6.7M The inclusion of dimensional data is not intended to imply that all the screws described are stock production sizes. Inch dimensioned standard machine screws may be found in MPAPS S-C-1.101-GS/PL. 2.0 CONTENTS: Page General 1 Design Consideration 2 Metric-Inch Re
8、lated Sizes 2 Threads 3 Thread Tolerances 3 Property Class 3 Color Coding 3 NUMBER: MPAPS S-CM-1.101-GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are re
9、quired to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 2 of 10 3.0 DESIGN CONSIDERATION: The following only will be considered as part of this standard for standardization purposes and manufacturing advantages in the case of drives. 1. Nominal Sizes Only ISO first choice series
10、 from 3 mm to 10 mm for all head styles except Hex Washer Head which will include 12 mm size. Present Navistar usage in equivalent inch sizes less than 3 mm or more than 10 mm is extremely limited. 2. Drives - ISO Type H Recess and Hexagon Washer Heads Cross recess is preferred over slotted by manuf
11、acturing experts because of less driver bit spin out, thus reducing costly rework. Hexagon Washer Heads, in addition to greater bearing area, have improved driving characteristics with the washer providing a shoulder for the socket plus protecting the assembly surface from socket disfigurement. 3. H
12、ead Styles - Flat and Raised (Oval) countersunk, Pan and Hexagon Washer Heads 4.0 METRIC-INCH RELATED SIZES: During the inch to metric design transition period, the following chart of related sizes can be used for reference. This information is not to be considered as a recommendation for substituti
13、ons but only as a means of determining approximate dimensional equivalents. Page Method of Designation 3 Policy for Selecting Parts for New Design 3 Bearing Surface 4 Eccentricity 4 Geometry of Hexagon Heads 4 Gaging for Lack of Fill 5 Depth of Recess 5 Tolerance On Length 5 Threads 5 Length of Thre
14、ad 5 Body Diameter 6 Ends of Screws 6 Material and Mechanical Properties 6 Non-Preferred Material 6 Finishes 7 Restricted Chemical Substances 7 Workmanship 7 Flat Head Cross Recess Machine Screws Pan Head Cross Recess Machine Screws Hexagon Washer Head Machine Screws 7 8 9 Technical Information 10 N
15、UMBER: MPAPS S-CM-1.101-GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page
16、3 of 10 Metric Series Approximate mm Inch Series 3 #4, #5 4 #6, #8 5 #10 6 #12, 1/4 8 5/16 10 3/8 12 1/2 5.0 THREADS: The ISO basic profile is essentially the same geometric configuration as the unified screw thread basic form. The threads will be coarse series, tolerance class 6g. 6.0 THREAD TOLERA
17、NCES: The medium class of fit 6H(Int) / 6g(Ext) is approximately the same as the 2A(Ext) / 2B(Int) allowance in the U.S. unified thread series for comparable size. For example: Thread Allowance M10 x 1.5 6H (Int) / 6g (Ext) 0.032 mm (.00126 in) 3/8 16 UNC 2A (Ext) / 2B (Int) .0013 in (0.033 mm) 7.0
18、PROPERTY CLASS: The property class designation for steel screws is equal to one-hundredth of the approximate proof load stress in megapascals (1 MPa = 1 N/mm2). 8.0 COLOR CODING: This is not recommended except in cases where adequate insurance is needed to prevent mixing of “metric parts“ with look-
19、alike “inch parts.“ The color blue is standard identifier used in some industries. This must be handled internally at individual plants where needed and is meant to be supplemental to the normal finish and easily deleted when the need for supplemental identification no longer exists. The supplementa
20、l blue color should not be used on materials such as stainless steel when used for cosmetic purposes, or phosphate coating which causes a loss of color identity. 9.0 METHOD OF DESIGNATION: Machine screws will be designated by size, length, general product description, material, finish and part numbe
21、r as follows: M3 x 10 Pan Head Machine Screw, Class 4.8, ZN, Part Number. The absence of a specification for pitch indicates that coarse thread is required; e.g., a coarse thread of the dimensions M10 x 1.5 is designated as “M10.“ 10.0 POLICY FOR SELECTING PARTS FOR NEW DESIGN: Approved parts are so
22、 designated to reduce variety of parts and assure maximum availability, interchangeability, and cost savings. For new design, parts shall be selected from “Approved“ part list only. Material: Class 4.8 Finish: Zinc Trivalent (ZN6A) and Phosphate Coating (PHC) Nominal Sizes and Lengths: See table fol
23、lowing. NUMBER: MPAPS S-CM-1.101-GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2
24、015 Page 4 of 10 Dimensions in millimeters: Nominal Screw Length Nominal Screw Size M3 M3.5 M4 M5 M6 M8 M10 M12* 5 X x 6 X x x 8 X x x x x 10 X x x x x x 12 X x x x x x x 14 X x x x x x x 16 X x x x x x x 20 X x x x x x x 25 X x x x x x x x 30 X x x x x x x x 35 x x x x x x x 40 x x x x x x 45 x x x
25、 x x 50 x x x x x 55 x x x x 60 x x x x 65 x x x 70 x x x 75 x x x 80 x x x 85 x x 90 x x 100 x x 110 x 120 x * Hexagon washer head machine screws only. Heavy top line is first length for countersunk screws. Dotted line is first length for headed screws. 11.0 BEARING SURFACE: The bearing surface of
26、flat bearing surface type machine screw heads will be at right angles to the axis of the screw shank within two (2) degrees. 12.0 ECCENTRICITY: Heads will not be eccentric with the machine screw bodies by more than three percent of the maximum head diameters or the maximum width across flats. Recess
27、 will not be eccentric with machine screw bodies by more than six percent of the maximum body diameter or 0.25 mm whichever is greater. Eccentricity is defined as one-half of the full indicator movement (FIM). 13.0 GEOMETRY OF HEXAGON HEADS: The dimensions across the flats of the head will be measur
28、ed at the point of maximum material, and the taper of the sides of the hexagon (the angle between one side and the axis) will not exceed two (2) degrees. A slight rounding of all edges and corners of the hexagon surfaces is permissible. For heads formed with an integral washer, the radius at the jun
29、ction of the sides of the hexagon and the top surface of the washer will not exceed the values given in section 28.0. NUMBER: MPAPS S-CM-1.101-GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corpo
30、rate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 5 of 10 14.0 GAGING FOR LACK OF FILL: The rounding due to lack of fill on all six corners of the hexagon will be reasonably uniform. The dimension across the corners of the head wil
31、l be such that it will be accepted by a ring gage as shown in section 28.0. The ring gage will be placed on the top only for hexagon washer head screws, and the head will protrude by an amount equal to or greater than the value given in section 28.0. 15.0 DEPTH OF RECESS: The depth of recess will be
32、 measured parallel to the axis of the screw for the intersection of the maximum diameter of the recess with the head surface to the bottom of the recess. Recess penetrating gauging depth values are included in the dimensional tables and the method of gaging and specifications for gages will be in ac
33、cordance with ISO 4757. 16.0 TOLERANCE ON LENGTH: The length of screw will be measured, parallel to the axis of screw, from the extreme point to the plane of the bearing surface for screws having flat bearing surface type heads, and to the intersection of the top surface of head with the head diamet
34、er for screws having countersunk-type heads. Nominal Screw Length Tolerance on Length, mm Up to 3 mm, inclusive +/-0.2 Over 3 to10mm , inclusive +/- 0.3 Over 10 to 16 mm, inclusive +/- 0.4 Over 16 to 50mm, inclusive +/- 0.5 Over 50 mm +/- 1.0 17.0 THREADS: Thread form, diameters, and associated pitc
35、hes are in accordance with ISO recommendations for coarse pitch series. Threads will be made to the tolerances of the medium class of fit (6g) external threads for plain or unplated screws as shown in ISO 965/2 - General Purpose Metric Screw Threads. 18.0 LENGTH OF THREAD: For screws having nominal
36、lengths equal to or shorter than listed in Column “L“ of the table following, the full thread will extend close to the head within limits specified in Column “A.“ Screws of longer nominal lengths will have a minimum length of full-formed threads as specified in Column “B.“ Tolerance of Length Dimens
37、ions in millimeters: Nominal Size L Nominal Length A Max Unthreaded Length Under Head B Min Full Form Thread Length M3 30 1 25 M3.5 50 1.2 38 M4 50 1.4 38 M5 50 1.6 38 M6 50 2 38 MS 50 2.5 38 M10 50 3 38 NUMBER: MPAPS S-CM-1.101-GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted
38、and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 6 of 10 19.0 BODY DIAMETER: The diameter of the body of machine screws will be within the limit
39、s specified in the table below: Dimensions in millimeters: Nominal Screw Size and Thread Pitch Body Diameter Max Min M3 x 0.5 3 2.58 M3.5 x 0.6 3.5 3.00 M4 x 0.7 4 3.43 M5 x 0.8 5 4.36 M6 x 1 6 5.25 M8 x 1.25 8 7.04 M10 x 1.5 10 8.86 M12 x 1.75 12 10.68 20.0 ENDS OF SCREWS: When screws are made with
40、 rolled threads, the lead formed at the end of the screw by the rolling operation will be regarded as providing the necessary chamfer, no other machining operation being necessary, and the end will be reasonably square with the axis of the screw threads. The first two threads will not be full thread
41、s and should not be used for load-carrying purposes. When screws are made with cut threads, the ends will be finished with a (nominal) 45 degree chamfer, the depth slightly exceeding the depth of thread. 21.0 MATERIAL AND MECHANICAL PROPERTIES: Steel machine screws will be manufactured to ISO Class
42、4.8 with the characteristics listed in the following table. 5.8 material is acceptable Required Characteristics ISO Class 4.8 ISO Class 5.8 * Tensile Strength, min MPa (psi) 420 520 60 900 75 400 Hardness, min (Rockwell) max (Rockwell) B71 B82 B95 B95 Stress Under Proof Load, MPa* (psi) 310 380 45 0
43、00 55 100 * Acceptable alternate material. * * Allowable permanent extension will be 12.5 micrometer. 22.0 NON-PREFERRED MATERIAL: Material Code Material Type Material Specification Remarks SST-304* Stainless Steel, Type 18-8 MPAPS A-37 Used for decorative exterior applications. Excellent corrosion
44、resistance. Nonmagnetic. SST-410* Stainless Steel, Type 410 MPAPS A-37 Higher strength/hardness obtained through heat treatment. Moderate corrosion resistance. Magnetic. * Stainless steels will be passivated per MPAPS A-37 finish type 5. NUMBER: MPAPS S-CM-1.101-GS/PL TITLE: Machine Screws REVISION:
45、 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 7 of 10 23.0 FINISHES: Screws will be furnished plain, plated
46、 or coated in accordance with the Navistar Engineering Material Specification and class listed below: Zinc Trivalent on steel (ZN6A) - MPAPS G-20, Class 6A. Phosphate Coating (PHC) - MPAPS G-1, Class B2. Black Oxide (BLO) - Standard with Manufacturer. 24.0 RESTRICTED CHEMICAL SUBSTANCES: Effective J
47、anuary 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the MPAPS B-50 specification. 25.0 WORKMANSHIP: Screws will be free from burrs, slivers and seams which might affect their serviceability. 26.0 FLAT HEAD CROSS RECESS MACHINE SCREWS: 26.1 Dimensions: Dimensions in millimeters: Nom Size Nom Pitch General Type H Recess A B R E D C Head Diameter Head Height Fillet Radius Thread Runout Penetration Gaging Depth Recess Dia Max Min2Max Min Max Max Max Min Ref M3 0.5 6.3 5.2 1.65 1.45 0.8 1 2.1 1.7 3.2 M4 0.7 9.4 8 2.7 2.45 1 1.4 2
