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 17 1.0 GENERAL: This standard conforms essentially with the Am
2、erican National Standard B-18.6.3 for various types of slotted and recessed head machine screws. Truss Head, Round Head and Binding Head Machine Screws are not approved for new design and should be replaced in new design by Pan Head Machine Screws. 2.0 RESTRICTED CHEMICAL SUBSTANCES: Effective Janua
3、ry 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the MPAPS B-50 specification. 3.0 CONTENTS: Page General 1 Restricted Chemical Substances 1 Policy for Selecting Parts for New Design 2 Service Parts Substitution Policy 2 Bearing Surface
4、3 Eccentricity 3 Head Height 3 Protrusion of Head 3 Slot Depth 4 Depth of Recess 4 Length 4 Threads 4 Length of Thread 4 Diameter of Body 5 Material 5 Finishes 5 Short Length Screws 5 Points 6 Workmanship 6 NAVISTAR, INC. Material, Parts, and Process Specifications (MPAPS) NUMBER: MPAPS S-C-1.101-GS
5、/PL Former Designation: ESP-C-1.101-GS TITLE: Machine Screws English Series (Noun Code 7450) CURRENT REV No.: 1506 DATE: June 2015 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: ESP-C-1.101-GS - May 2007 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CU
6、RRENT 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 determine the applicability
7、 of regulatory limits prior to use. Change Notice: Changed to New MPAPS format; Combined GS, PP, NPP, NR. NUMBER: MPAPS S-C-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 Technic
8、al Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 2 of 17 Flat Head Cross Recess Machine Screws 7 Flat Head Slotted Machine Screws 8 Oval Head Cross Recess Machine Screws 9 Oval Head Slotted Machine Screws 10 Pan Head Cross Recess Machine Scre
9、ws 11 Pan Head Slotted Machine Screws 12 Fillister Head Cross Recess Machine Screws 13 Round Head Slotted Machine Screws 14 Hexagon Head Machine Screws 16 Technical Information 17 4.0 POLICY FOR SELECTING PARTS FOR NEW DESIGN: Approved parts are so designated to reduce variety of parts and assure ma
10、ximum availability, interchangeability and cost savings in volume buying. For new design, parts shall be selected from “Approved“ part list only. Head Types: Flat, Oval, Pan, Hex Drive: Cross Recess, ANSI Type 1, (Phillips), and Hex Diameters: 6, 8, 10, 1/4, 5/16, 3/8 Threads: Coarse Finishes: Zinc
11、with Chromate (ZND), Phosphate Coated (PHC) Lengths: As shown below: 5.0 SERVICE PARTS SUBSTITUTION POLICY: In the event that engineering does not indicate a “Do not substitute“ in engineering specifications, the following substitutions may be implemented in service. This policy is the result of a p
12、roposal circulated April 20, 1981, and subsequently approved by engineering departments worldwide. 5.1 Flat Head Machine Screws To Be Replaced Service Replacement Slotted or Cross Recess, plain (PLN) finish Zinc with chromate (ZN6A) cross recess or (ZN6A) slotted (if cross recess is not set up for s
13、ervice. Slotted, phosphate coated (PHC) finish Cross Recess, phosphate coated (PHC) finish Slotted, zinc with chromate (ZN6A) finish Cross Recess, zinc with chromate (ZN6A) finish NUMBER: MPAPS S-C-1.101- GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent outs
14、ide 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 17 5.2 Pan Head Machine Screws To Be Replaced Service Replacement Slotted or Cross Recess, plain (PLN) finish Zinc
15、 with chromate (ZN6A) cross recess or (ZN6A) slotted (if cross recess is not set up for service. Slotted, phosphate coated (PHC) finish Cross Recess, phosphate coated (PHC) finish Slotted, zinc with chromate (ZN6A) finish Cross Recess, zinc with chromate (ZN6A) finish 5.3 Fillister Head Machine Scre
16、ws To Be Replaced Service Replacement Slotted or Cross Recess, plain (PLN) finish Zinc with chromate (ZN6A) cross recess or (ZN6A) slotted (if cross recess is not set up for service. Slotted, zinc with chromate (ZN6A) finish Cross Recess, zinc with chromate (ZN6A) finish 5.4 Round Head Machine Screw
17、s To Be Replaced Service Replacement Slotted, plain finish Pan head, cross recess, zinc dichromate (ZN6A) finish or slotted (if cross recess is not set up for service). 6.0 BEARING SURFACE: The bearing surface of flat bearing surface type machine screw heads will be at right angles to the axis of th
18、e screw shank within 2 degrees. 7.0 ECCENTRICITY: Heads will not be eccentric with the machine screw bodies by more than 3 percent of the maximum head diameters. Slots will not be eccentric with machine screw bodies by more than 6 percent of the maximum body diameter of .010 inch whichever is greate
19、r. Eccentricity is defined as one-half of the full indicator movement (FIM). 8.0 HEAD HEIGHT: All dimensions pertaining to head height specified in the dimensional tables will be measured parallel to the axis of screw and those relating to the top of head will represent a metal to metal measurement.
20、 In other words, any truncation of rounded head contours due to the slot or recess will not be considered part of the head height. Total or overall head heights will be measured from the top of the head to the plane of the bearing surface for flat bearing surface type heads, to the plane of the unde
21、rcut for undercut countersunk heads, and to the junction of conical bearing surface with the basic screw diameter for countersunk heads. Head side heights will be measured from the intersection of the top surface of head with the head diameter to the plane of the bearing surface for flat bearing sur
22、face type heads, to the plane of the undercut for undercut countersunk heads, and to the junction of conical bearing surface with the basic screw diameter for countersunk heads. On countersunk heads, the junction of conical bearing surface with the basic screw diameter may not necessarily be the sam
23、e as the actual junction of head with shank and the head height delineating the conical bearing surface is a reference dimension. 9.0 PROTRUSION OF HEAD: Except for the 0 and 1 size undercut heads, suitability of flat head screws for application in countersinks may be determined by checking the “T“
24、dimension in a protrusion gage. Protrusion gages will have a hardness of not less than Rockwell C60. Sharpness of NUMBER: MPAPS S-C-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
25、 Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 4 of 17 gaging edge will be that which is obtained by lapping the hole and the top surface of the gage. Variation in gaging diameter from the value given in the table will require propo
26、rtional correction of protrusion gaging values. 10.0 SLOT DEPTH: The depth of slot in slotted head screws will be measured parallel to the axis of screw from the top of the head to the intersection of the bottom of the slot with the head surface or bearing surface. 11.0 DEPTH OF RECESS: The depth of
27、 recess will be measured parallel to the axis of the screw from the intersection of the maximum diameter of the recess with the head surface to the bottom of the recess. Recess penetration gaging depth values are included in the dimensional tables and the method of gaging and specifications for gage
28、s are covered in MPAPS S- C- 90.101-GS/PL Nominal Screw Length Nominal Screw Size 0 thru 12 1/4 thru 3/4 Tolerance on Length Up to 1/2 in, Incl -.02 -.03 Over 1/2 to 1 in, Incl -.03 -.03 Over 1 to 2 in, Incl -.06 -.06 Over 2 in -.09 -.09 12.0 LENGTH: The length of screw will be. measured, parallel t
29、o 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 diameter for screws having countersunk type heads. 13.0 THREADS: Threads will be Unified Standard, Class
30、 2A, UNC or UNF series or UNRC or UNRF series with radius root, optional with manufacturer. Class 2A limits will apply to plain finish (unplated or uncoated) screws and to plated or coated screws before plating or coating. For screws with additive finish the maximum diameters of Class 2A may be exce
31、eded by the amount of the allowance, that is, the basic diameters (the Class 2A maximum diameters plus the allowance) will apply to plated or coated screws after plating or coating. The major diameter of plated or coated screws may approach, but will not be less than the Class 2A minimum limit. 14.0
32、 LENGTH OF THREAD: Sizes No. 5 and Smaller. Screws of nominal lengths equal to 3 diameters and shorter will have full form threads extending to within one pitch (thread) of the bearing surface of the head, or closer, if practicable. Nominal lengths greater than 3 diameters, up to and including 1-1/8
33、 inch, will have full form threads extending to within two pitches (threads) of the bearing surface of the head, or closer if practicable. Screws of longer normal lengths will, unless otherwise specified, have a minimum length of full form thread of 1.00 inch. Sizes No. 6 and Larger. Screws of nomin
34、al lengths equal to 3 diameters and shorter will have full form threads extending to within one pitch (thread) of the bearing surface of the head, or closer, if NUMBER: MPAPS S-C-1.101- GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc.
35、or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 5 of 17 practicable. Nominal lengths greater than 3 diameters, up to and including 2 inch, will have full form threads extending to within
36、 two pitches (threads) of the bearing surface of the head, or closer if practicable. Screws of longer nominal lengths will, unless otherwise specified, have a minimum length of full form thread of 1.50 inch. 15.0 DIAMETER OF BODY: The diameter of body on machine screws will not be less than the Clas
37、s 2A thread minimum pitch diameter no greater than the basic major diameter of the thread. 16.0 MATERIAL: Material Code Material Type Material Specification Remarks CST Carbon steel SAE 1010-1020 BRS Brass, Alloy C36000 CEMS C-3 SST-304* Stainless Steel, Type 18-8 MPAPS A-37 Used for decorative exte
38、rior applications. Excellent corrosion 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. 17.0 FINISHES: As desi
39、gnated by part number, screws will be furnished plain, plated or coated in accordance with the NAVISTAR MPAPS and class listed below: Zinc Trivalent, Class 6A (ZN6A) - G-20, Class 6A. Phosphate Coating (PHC) - G-1, Class B2. Chromium Bright (CRB) - G-19, Part III, Class 3 CRB or Class 5 CRB as dicta
40、ted by threads per inch. Chromium Dull (CRD) - G-19, Part III, Class 3 CRD or Class 5 CRD as dictated by threads per inch. Nickel Bright (NIB) - G-19, Part III, Class 3 NIB, or Class 5 NIB as dictated by threads per inch. Nickel Dull (NID) - G-19, Part III, Class 3 NID or Class 5 NID as dictated by
41、threads per inch. Black Enamel (BLE) - Standard with manufacturer. Black Oxide (BLO) - Standard with manufacturer. Blued (BLU) - Standard with manufacturer. 18.0 SHORT LENGTH SCREWS: As shown in Table 1, Flat or Oval head screws having lengths equal to or less than the length listed will have head u
42、ndercut by an amount which reduces the head height to 70 percent of “E.” A corresponding reduction will also apply to slotted or recess depths. Radius dimensions shown will also apply. NUMBER: MPAPS S-C-1.101- GS/PL TITLE: Machine Screws REVISION: 1506 This document is restricted and may not be sent
43、 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 17 TABLE 1 - DIMENSIONS FOR UNDERCUT HEAD Dimensions in inches: Nominal Size Nominal Screw Length Equal to or
44、 Less Than E1 R1 FLAT HEAD OVAL HEAD Head Height Radius H1 M1 H1 M1 Slot Depth Cross Recess Depth Cross Recess Depth Slot Depth Cross Recess Depth Cross Recess Diameter Max Min Max Max Min Max Min Max Min Max Min Max Min Min Max 0 1/8 .025 .018 .009 .011 .007 .043 .027 .069 .056 .028 .022 .045 .027
45、.074 .061 1 1/8 .031 .023 .011 .014 .009 .051 .035 .077 .064 .034 .027 .048 .030 .077 .064 2 1/8 .036 .028 .013 .016 .011 .056 .040 .095 .082 .040 .033 .069 .052 .112 .099 3 1/8 .042 .033 .015 .019 .012 .063 .047 .102 .089 .047 .038 .081 .064 .124 .111 4 3/16 .047 .038 .017 .022 .014 .078 .062 .117
46、.103 .053 .043 .094 .077 .136 .123 5 3/16 .053 .043 .019 .024 .016 .089 .073 .128 .115 .059 .048 .085 .061 .158 .145 6 3/16 .059 .048 .021 .027 .017 .078 .055 .146 .133 .065 .053 .105 .080 .178 .165 8 1/4 .070 .058 .025 .032 .021 .106 .083 .174 .161 .078 .064 .119 .095 .192 .179 10 5/16 .081 .068 .0
47、28 .037 .024 .121 .098 .189 .176 .090 .074 .137 .113 .209 .196 12 3/8 .092 .078 .032 .043 .028 .121 .098 .233 .220 .103 .085 .152 .128 .270 .257 1/4 7/16 .107 .092 .038 .050 .032 .136 .113 .250 .237 .119 .098 .173 .148 .290 .277 5/16 1/2 .134 .116 .047 .062 .041 .168 .146 .317 .304 .149 .124 .226 .2
48、02 .381 .368 3/8 9/16 .161 .140 .056 .075 .049 .216 .194 .365 .352 .179 .149 .245 .221 .400 .387 7/16 5/8 .156 .133 .066 .072 .045 .245 .223 .393 .380 .184 .154 .257 .233 .410 .397 1/2 3/4 .156 .130 .075 .072 .046 .261 .242 .409 .396 .204 .169 .269 .245 .422 .409 19.0 POINTS: Machine screws are regu
49、larly supplied with a plain sheared end, not pointed. However, for specific applications and under separate part number, screws up to certain lengths may be obtained with header points, see Table 2. Pointing of longer lengths will require machining. TABLE 2 DIMENSIONS FOR HEADER POINTS Dimensions in inches: Nominal Size Threads Per Inch P C Nominal Size Threads Per Inch P C Point Diameter Nom Screw Length Point Diameter Nom Screw Length Max Min Max Max Min Max 4 40 .074 .065 1/2 12 28 .156 .141 1-3/8 4 48 .079 .070 1/2 1/4 20 .170 .153 1-1/2
