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-D-40.101-GS/PL Former Designation: ESP-D-40.101-GS TITLE: Self-Drilling Tapping Screws - English Series (Noun Code 7450) CURRENT REV No.: 1506 DATE: June 2015 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: ESP-D-40.101-GS - August 2006
3、 PRINTED COPIES OF THIS 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
4、 and health practices and to determine the applicability of regulatory limits prior to use. Change Notice: Changed to New MPAPS format; Combined GS, PP. 1.0 GENERAL: This standard covers requirements for carbon steel self-drilling tapping screws suitable for use in general engineering applications.
5、The objective of this standard is to insure that carbon steel self-drilling tapping screws drill a hole and form or cut mating threads in material into which they are driven, without deforming their own thread and without breaking during assembly. It is the intent that all types of self-drilling tap
6、ping screws will meet the mechanical and performance requirements specified in this standard with the only difference between types being in their dimensional characteristics. 2.0 CONTENTS: Page General 1 Screw Types and Application 2 Head Types 3 Dimensional Requirements 3 Threads and Points 4 Mate
7、rial, Heat Treatment, Case Hardness and Ductility 5 Finish 5 Restricted Chemical Substances 6 Hydrogen Embrittlement Test 6 Test Methods and Performance Requirements 6 Policy for Selecting Parts for New Design 7 Reference Data 7 Part List 10 Technical Information 10 NUMBER: MPAPS S-D-40.101-GS/PL TI
8、TLE: Self-Drilling Tapping 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 2 of 10 3.0 SCREW
9、TYPES AND APPLICATION: The two types of self-drilling tapping screws covered by this standard are designated and described as follows: 3.1 Type BSD: Type BSD screws will have spaced threads (same as ANSI Type B tapping screws) with drill points of varying configuration, designated Style 2 and Style
10、3, designed to accommodate different panel thickness conditions as delineated in Table 1. 3.2 Type CSD: Type CSD screws will have threads of machine screw diameter-pitch combinations approximately Unified Form with drill points of varying configuration, designated Style 2 and Style 3, designed to ac
11、commodate different panel thickness conditions and delineated in Table 1. Type CSD screws are not subject to thread gaging but will meet dimensions specified in this standard. They are intended for application where the use of a machine screw pitch thread is preferred over the spaced thread. Table 1
12、 - Self-Drilling Tapping Screw Selection Chart Screw Type Point Style Nominal Screw Size paRecommended Panel Thickness, in. BSD and CSD 2 4 .035 - .080 max 6 .035 - .090 max 8 .035 - .100 max 10 .035 - .110 max 12 .035 - .140 max 1/4 .035 - .175 max 3 6 .090 - .110 8 .100 - .140 10 .110 - .175 12 .1
13、10 - .210 1/4 .110 - .210 If the panel to be drilled is comprised of two or more layers. See Figures 1B and 1C, the gap between the layers (which might consist of a sealing strip, air space caused by warpage, etc or just the separation caused by the pressure exerted by the driver) must be considered
14、 in determining the point style for the particular fastener. Using a self-drilling tapping screw as covered in this standard in a multi-layer application with an excessive gap could result in point breakage since the tapping in one layer begins before completion of the drilling of the other layers a
15、nd since the advancement of the screw in the tapping operation is much faster than in the drilling operation. FIGURE 1 - TYPICAL PANEL CONFIGURATIONS For multipanel applications which exceed the thickness tabulated, clearance holes should be provided in the uppermost panel or panels to reduce the th
16、ickness to be drilled by the screw. Driving tools which operate between 1800 and 3000 rpm are commonly used for self-drilling tapping screw applications. NUMBER: MPAPS S-D-40.101-GS/PL TITLE: Self-Drilling Tapping Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar
17、, 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 10 Torque output of the driver should be equivalent to the torque required to drive a comparable standard thread forming or th
18、read cutting tapping screw in a predrilled hole. .035 is minimum steel sheet thickness recommended, using self-drilling tapping screws described in this standard. To avoid skidding, self-drilling screws must be driven perpendicular to the work surface unless a dimple is provided. Curved surfaces or
19、angular drilling requires controlled conditions, a modification of the drill point and/or a dimple. Magnetic bits and sockets are not recommended for sealing applications or when material thickness is near the maximum drilling limit of the particular screw (see Table 1) because of possible chip coll
20、ection under the head. Excessive drilling pressure, especially during the initial penetration of the drill point, increases the amount of material being removed by the flutes and could result in drilling torques in excess of the strength of the drill point. 4.0 HEAD TYPES: The head types covered by
21、this specification include, pan, oval, flat and hex washer as specified in SAE J478 and ANSI B18.6.4 ANSI Type I recess (Phillips) is the only cross recess considered in this standard. Slotted head screws and hex (non-washer) head screws are not recommended for self-drilling screws. 5.0 DIMENSIONAL
22、REQUIREMENTS: 5.1 General Dimensions: Dimension and general specifications applicable to heads, body, and screw length for Type BSD and Type CSD screws will conform to those specified for Type B and Type C tapping screws, respectively, as specified in SAE J478 or ANSI B 18.6.4 or Navistar standards
23、for flat, oval and pan head (except for #6 size which has extra .018 max and min heights) cross recess and hex washer head tapping screws in section D, except as specified in paragraph “Heads“ which follows. 5.2 Heads: The underside on all non-countersunk styles of heads on milled point self-drillin
24、g screws may be chamfered at the periphery of head in accordance with the dimensions specified in Figure 2 and Table 2. FIGURE 2 - HEAD CHAMFERS ON MILLED POINT SCREWS NUMBER: MPAPS S-D-40.101-GS/PL TITLE: Self-Drilling Tapping Screws REVISION: 1506 This document is restricted and may not be sent ou
25、tside 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 10 Table 2 - Head Chamfer Dimensions For Milled Point Self-Drilling Tapping Crews in Figure 2 Nominal Screw Size
26、 U R1R2Washer Thickness Chamfer Height Hex Washer Hds Chamfer Height Recessed Heads Max Min Ref Ref 4 .030 .020 .015 .015 6 .040 .025 .015 .015 8 .050 .035 .020 .015 10 .050 .035 .020 .020 12 .050 .035 .020 .020 1/4 .060 .040 .025 .020 5.3 Eccentricity: Eccentricity is defined as one-half of the ful
27、l indicator movement (FIM). Eccentricity of Hex and Hex Washer Heads - Hex and hex washer heads will not be eccentric with the axis of screw by an amount equal to more than 4% of the basic screw diameter. Eccentricity of Recess - The recess in recessed head screws will not be eccentric with the axis
28、 of screw by an amount equal to more than 4% of the basic screw diameter. 5.4 Length of Thread: 5.4.1 Type BSD Screws - For screws of nominal lengths equal to or shorter than 1.50 inches, the full form threads will extend close to the head such that the specified minor diameter limits are maintained
29、 to within one pitch (thread), or closer if practicable, of the underside of the head. See Figure 3. For screws of nominal lengths longer than 1.50 inches, the length of full form thread will be as specified. 5.4.2 Type CSD Screws - For screws of nominal lengths equal to or shorter than 1.50 inches,
30、 the full form threads will extend close to the head such that the specified major diameter limits are maintained to within two pitches (threads), or closer if practicable, of the underside of the head. See Figure 4. For screws or nominal lengths longer than 1.50 inches. the length of full form thre
31、ad will be as specified. 6.0 THREADS AND POINTS: The threads and points applicable to screws covered by this standard are generally described under paragraph “Screw Types and Applications.“ They will conform to the dimensions specified in Table 2 of this document. NUMBER: MPAPS S-D-40.101-GS/PL TITL
32、E: Self-Drilling Tapping 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 5 of 10 7.0 MATERIAL
33、, HEAT TREATMENT, CASE HARDNESS AND DUCTILITY: Refer to SAE J78 (latest SAE Handbook) for complete specifications and test methods. The following limited information is published as a convenient reference. 7.1 Material and Chemistry: Screws will be made form cold heading quality, killed steel wire c
34、onforming to the following chemical composition: Composition Limits, % by Weight Analysis aCarbon Manganese Max Min Max Min Ladle Check .25 .27 .15 .13 1.65 1.71 .70 .64 aLadle analyses are shown for informational purposes. Check analyses are mandatory and refer to individual determinations on uncar
35、burized or core portions of screws. 7.2 Case Depth: Screws shall have a case depth conforming to the tabulation below: Case depth shall be measured at a mid-point between crest and root on the thread flank. 7.3 Case Hardness: Screws will have a case hardness equivalent to Rockwell C 52-58. For routi
36、ne quality control purposes (where case depth and geometry of screw permit), case hardness may be measured on end, shank, or head using Rockwell 15 N. As an alternate, or where this method is not applicable, a microhardness instrument with a Knoop or diamond pyramid indenter and a 500 g load may be
37、used. In such cases, measurements will be made on the thread profile of a properly prepared longitudinal metallographic specimen. 7.4 Core Hardness: Screws shall have a core hardness equivalent to Rockwell C-32-40, when measured at mid-radius of a transverse section through the screw taken at a dist
38、ance sufficiently behind the point of the screw to be through the full minor diameter. 7.5 Ductility: Heads of screws shall not separate completely from the shank when a permanent deformation of 5 deg is induced between the plane of the under head bearing surface and a plane normal to the axis of th
39、e screw when tested as follows: The sample screw shall be inserted into a drilled hole in a hardened wedge bloc, or other suitable device, and an axial compressive (or impact) load applied against the top of the screw head. Loading shall be continued until the plane for the under head bearing surfac
40、e is bent permanently through 5 deg with respect to a plane normal to the axis of the screw. 8.0 FINISH: As designated by part number, screws will be furnished plain, plated or coated in accordance with the MPAPS and class listed below. Zinc Trivalent (ZN6A) MPAPS G-20, Class 6A. Phosphate Coating (
41、PHC) MPAPS G-1, Class B-2. Nominal Screw Size Case Depth, in. Max Min 4 and 6 8 thru 12 1/4 0.007 0.009 0.011 0.002 0.004 0.005 NUMBER: MPAPS S-D-40.101-GS/PL TITLE: Self-Drilling Tapping Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced witho
42、ut permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 6 of 10 Chromium Bright (CRB) CEMS G-19 Part III, Class 3 or 5 depending on pitch. All shipments will be uniform in color, brightness and luster, and they wi
43、ll be free from loose scale, grease and oil. 9.0 RESTRICTED CHEMICAL SUBSTANCES: Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the MPAPS B-50 specification. 10.0 HYDROGEN EMBRITTLEMENT TEST: Steel screws plated or coate
44、d and subject to hydrogen embrittlement, will be suitably treated subsequent to the plating or coating operation to obviate such embrittlement. Electroplated screws will be subjected to the hydrogen embrittlement test in SAE J78. 11.0 TEST METHODS AND PERFORMANCE REQUIREMENTS: Refer to SAE J78 (late
45、st SAE Handbook) for complete specifications and test methods. 11.1 Torsional Strength and Hydrogen Embrittlement Test: Table 1 gives minimum torsional strength torques and the hydrogen embrittlement test torques for various screw sizes. For test procedure details, reference SAE J78. 11.2 Drill Driv
46、e Test: The maximum time required for a screw to drill and thread a hole completely through a test plate for the stated test conditions are given in Table 2. 11.3 Drill Hole Size: The following test is to insure that the drill point does not drill an oversize hole that would cause a loss of diametri
47、cal thread engagement and result in premature strippage of the mating thread produced in the sheet metal. The diameter of the hole drilled by the screw shall not exceed the point diameter of the screw by more than .005 inch. 11.4 Drill Hole Size Test: The sample screw shall be inserted through a sle
48、eve or collar having an inside diameter of approximately 0.010 in. greater than the major diameter of the screw. The length of sleeve or collar should be such that sufficient unthreaded point length extends through the sleeve or collar to drill a hole through the minimum thickness material specified
49、 in Table 2 without thread pickup. After the hole is drilled in the test plate, the screw shall be removed and the diameter of the drilled hole gaged. 11.5 Failure Torque Test: Starting torque is defined as the maximum amount of torque required to form and/or cut a mating thread through the test panel. Failure torque is defined as the minimum torque required to fail the mating thread in the test panel. To assure satisfactory performance of start to failure relationship, te
