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 9 NAVISTAR, INC. Material, Parts, and Process Specifications (
2、MPAPS) NUMBER: MPAPS S-CM-29.101-GS/PL Former Designation: ESP-CM-29.101-GS TITLE: Flanged 12-Point Screws Metric Series CURRENT REV No.: 1506 DATE: June 2015 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: ESP-CM-29.101-GS - March 2011 PRINTED COPIES OF THIS
3、DOCUMENT MUST 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 an
4、d to determine the applicability of regulatory limits prior to use. Change Notice: Changed to New MPAPS format; Combined GS, GI, PP. 1.0 GENERAL: Implementation of this standard must be in accordance with the policies and procedures outlined in MPAPS S-A-0.101. There may also be supplemental group i
5、nstructions in regard to use of metric standards that should be taken into account. As of this printing, there is no metric Navistar or National standard on this product. The specifications are based upon supplier information and user requirements. The inclusion of dimensional data is not intended t
6、o imply that all the screws described are stock production sizes. Inch dimensioned screws may be found in MPAPS S-C-29.101-GS/PL. 2.0 RESTRICTED CHEMICAL SUBSTANCES: Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the MPA
7、PS B-50 specification. 3.0 CONTENTS: Page General 1 Restricted Chemical Substances 1 Design Consideration 2 Metric-Inch Related Sizes 2 Threads 2 Thread Tolerances 2 Thread Length Formula 3 Property Class 3 Color Coding 3 Method of Designation 3 Policy for Selecting Parts for New Design 3 Top of Hea
8、ds 4 Corner Fill 4 NUMBER: MPAPS S-CM-29.101-GS/PL TITLE: Flanged 12-Point 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
9、Navistar, Inc. JUNE 2015 Page 2 of 9 4.0 DESIGN CONSIDERATION: Coarse thread series only will be considered as part of this standard, because of the following advantages: Less tendency to cross thread. Resists nicking and has less stress concentration at the thread roots. Less likely to be seriously
10、 affected by decarburization and oversize minor diameter of internal threads. Flanged 12-point screws are interchangeable with hex socket head capscrews. Because of larger gripping surface which permits better wrenching, 12-point screws from 12 mm size and up are preferred over hex socket head capsc
11、rews. 5.0 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 substitutions but only as a means of determining approximate dimensional equivalen
12、ts. Metric Series mm Approximate Inch Series 6 1/ 4 8 5/16 10 3/8, 7/16 12 1/ 2 16 9/16, 5/8 20 6.0 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. 7.0 THREAD TOLERANCES: The
13、 medium class of fit 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) Page Wrenching Height 4 Bearing
14、 Surface 4 Screw Length 4 Body Diameter 4 Threads 4 Thread Length 4 Thread Runout 5 Marking 6 Material Finishes Workmanship 6 6 6 Part List 9 Technical Information 9 NUMBER: MPAPS S-CM-29.101-GS/PL TITLE: Flanged 12-Point Screws REVISION: 1506 This document is restricted and may not be sent outside
15、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 3 of 9 8.0 THREAD LENGTH FORMULA: The thread lengths shown in Table 1 are based on the formulas shown below: Millimeters No
16、minal Length Formula for Thread Length Over To - 125 2d + 6 125 200 2d + 12 200 - 2d + 25 D = Nominal Diameter of the Screw 9.0 PROPERTY CLASS: The property class designation for flanged 12-point screws is equal to one-hundredth of the approximate proof load stress in megapascals (1 MPa = 1 N/mm2).
17、10.0 COLOR CODING: Not recommended, except in cases where adequate insurance is needed to prevent mixing of “metric parts“ with look-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
18、 supplemental to the normal finish and easily deleted when the need for supplemental identification no longer exists. The supplemental blue color should not be used on material such as stainless steel which is specified for cosmetic purposes, or phosphate coating which may cause a loss of color iden
19、tity 11.0 METHOD OF DESIGNATION: 12-point screws will be designated by size, length, word description, material, special feature, if any, finish, and part number as shown in the following examples: M10 x 50, 12-Point Screw, Class 12.9, PHC, Part Number The absence of a specification for pitch indica
20、tes that coarse thread is required; e.g., a coarse thread of the dimensions M10 x 1.5 is designated as “M10.” 12.0 POLICY FOR SELECTING PARTS FOR NEW DESIGN: Approved parts are so designated to reduce the variety of parts and to assure maximum availability, interchangeability, and cost savings. For
21、new design, parts shall be selected from “Approved“ part list only. Nominal Sizes: M6, M8, M10, M12, M16, M20, and M24 Material: Class 10.9 and 12.9. Finish: Plain (PLN), Phosphate Coating (PHC) per MPAPS G-1, Zinc Aluminum Clear (ZACLR) per MPAPS G-4518, Type I. Dimensions in millimeters: Lengths:
22、First Length 12 12 20 25 30 35 Diameter M6 M8 M10 M12 M16 M20 All diameters - 2 mm increments up to 20 mm 5 mm increments over 20 thru 90 mm 10 mm increments over 90 thru 200 mm 20 mm increments over 200 mm NUMBER: MPAPS S-CM-29.101-GS/PL TITLE: Flanged 12-Point Screws REVISION: 1506 This document i
23、s 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 4 of 9 13.0 TOP OF HEAD: The top of head may be full form or indented at the optio
24、n of the manufacturer. If full form, the top of head will be chamfered or rounded with the diameter of chamfer circle or start of rounding being equal to the specified maximum width across flats within a tolerance of -15%. If the top of head is indented, the periphery may be rounded. 14.0 CORNER FIL
25、L: The rounding due to lack of fill at all 12 corners of the head will be reasonably uniform. 15.0 WRENCHING HEIGHT: The wrenching height will be measured, parallel to the axis of screw, from the intersection of the top contour of flange with any corner of head to the top of the head. 16.0 BEARING S
26、URFACE: The bearing surface shall be conical 0.75 0.50 degrees concave from the plane formed by the bearing surface diameter. The plane of the bearing face will be perpendicular to the axis of screw within the runout limit specified in the dimensional chart. Measurement of runout will be made as clo
27、se to the periphery of bearing face as possible while the screw is held in a collet or other gripping device at a distance equal to one screw diameter from the underside of the head. 17.0 SCREW LENGTH: The nominal length is the distance from the underside of the head to the furthest end of the threa
28、ded portion including any chamfer or radius. Tolerances for nominal screw lengths are shown in the following. Dimensions in millimeters: Nominal Length Nominal Size of Screw M5 thru M8 M10 thru M16 M20 To 10 mm, incl 0.3 0.3 Over 10 to 18 mm, incl 0.4 0.4 Over 18 to 30 mm, incl 0.4 0.4 0.6 Over 30 t
29、o 50 mm, incl 0.5 0.8 1.3 Over 50 to 80 mm, incl 0.6 1.0 1.5 Over 80 to 120 mm, incl 0.7 1.1 1.7 Over 120 to 180 mm, incl 1.3 1.3 2.0 Over 180 to 240 mm, incl 2.3 2.3 2.3 18.0 BODY DIAMETER: On screws threaded full length, the diameter of the screw under the head will not be less than the specified
30、minimum pitch diameter of the thread. 19.0 THREADS: Thread form, diameters, and associated pitches are in accordance with ISO Recommendations for coarse pitch series. Threads will be made to the tolerances of the medium class of fit (6g) for plain or unplated screws as shown in ISO 965/11, General P
31、urpose Metric Screw Threads. 20.0 THREAD LENGTH: The length of thread on screws shall be controlled by the maximum grip gaging length, Lg, and the minimum body length, Ls, as set forth in the following paragraphs. Grip gaging length, Lgmax, is the distance, measured parallel to the axis of the screw
32、, from the plane formed by the bearing circle diameter to the face of a noncounterbored or noncountersunk standard GO thread ring gage assembled by hand as far as the thread will permit. For standard diameter-length combinations of screws, the values for Lgmax are specified in Table 2. For diameter-
33、length combinations not listed in Table 2, the maximum grip gaging length, as calculated NUMBER: MPAPS S-CM-29.101-GS/PL TITLE: Flanged 12-Point Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Stan
34、dards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 5 of 9 and rounded to one decimal place, shall be equal to the nominal screw length, L, minus the basic thread length, M, as specified in Table 1. Body length, Lsmin, is the distance, measured paralle
35、l to the axis of the screw, from the plane formed by the bearing circle diameter to the last scratch of thread or the top of the extrusion angle, whichever is closer to the head. For standard diameter-length combinations of screws, the values of Lsmin are specified in Table 2. For diameter-length co
36、mbinations not listed in Table 2, the minimum body length, as calculated and rounded to one decimal place, shall be equal to the maximum grip gaging length (as computed) minus the maximum transition length as given in Table 1 Lgmin = Lgmax (X). Lsmin shall be used as a criterion for inspection. Nomi
37、nal thread length, M, as specified in Table 1 is a reference dimension intended for calculation purposes only, and is the distance measured parallel to the axis of the screw, from the extreme end of the screw to the last complete (full form) thread. Transition thread length, (X), as specified in Tab
38、le 1 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 shal
39、l not exceed the actual major diameter of the complete (full form) threads. 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. The length of thread will be the distance from the end of the s
40、crew, including any chamfer or radius to the leading face of a screw ring gage with no internal chamfer which has been screwed as far as possible onto the screw by hand. See table on page 7 for standard thread lengths. Screws that are too short for minimum thread lengths as shown in table on last pa
41、ge will be threaded to permit a screw ring gage being screwed by hand to within a distance from the underside of the head not exceeding two and one-half times the pitch. 21.0 THREAD RUNOUT: Screws will screw at least two pitches into hardened gages such as illustrated below. The diametral clearance
42、will be 0.79 mm for screws up to and including M20 and 1.57 mm for screws larger than M20. A - Thread ring gage set to Class 6H max pitch diameter. B - Sleeve. C - Attachment Screws. D - Max diameter of screw plus diametral clearance. F - Positioning and setting plug for adjusting ring gage to Class
43、 6H diameter and centering sleeve. Thread PD = Class 6H Max. L - Length of screw minus one screw diameter not to exceed 76.2 mm. NUMBER: MPAPS S-CM-29.101-GS/PL TITLE: Flanged 12-Point Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without
44、permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 6 of 9 22.0 MARKING: The manufacturers symbol and property class will be embossed or indented on the top of the head or on the top of the flange. EXAMPLES OF TH
45、E MARKING OF SCREWS Property Class Designation Marking of Screws Property Class Designation 10.9 12.9 23.0 MATERIAL: Property Class 10.9 and 12.9 per MPAPS F-31, Part I. The steel used will be such that the finished product possesses the mechanical properties listed. Required Characteristics Class 1
46、0.9 Class 12.9 Tensile Strength, Min MPa (psi) 1040 150839 1220 177000 Heat Treatment, Min Max (Rockwell) (Rockwell) C33 C39 C38 C43 24.0 FINISHES: Screws will be furnished plain, plated, or coated in accordance with the Navistar Engineering Material Specification and class listed below. Plain (PLN)
47、 - Free from dirt and dust and coated with a light oil film. Phosphate Coated (PHC) MPAPS G-1, Class B-2. Zinc Aluminum Clear (ZACLR) MPAPS G-4518, Type I High tensile strength steel components such as flanged 12-point screws, are more susceptible to embrittlement by hydrogen, therefore, electroplat
48、ing is not recommended for these products. However, if chemical or electrochemical surface coating cannot be avoided, the plated 12-point screws must be heated at a temperature sufficiently high and for a period sufficiently long to remove the hydrogen. 25.0 WORKMANSHIP: Screws will be free from burrs, seams, laps, loose scale, and any defects that affect serviceability. Table 1: Flanged 12-Point Screws MXYZ
