METRIC
SCREW THREADS: M PROFILE
(Revision of ASME B1.13M-1995)
METRIC SCREW THREADS: M PROFILE
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CONTENTS
Foreword viCommittee Roster vii
1.1 1.2 Scope Interchangeability 11.3 References .......1.4 1.5 Reference Temperature Acceptability 11.6 1.7 General Symbols Units 2 21.8 Federal Govermment Use 2
Terminology
2.1 Definitions
Screw Thread Profile
Design M Profiles Basic M Thread Profile ....
3.1 3.23.3 Crest and Root Forms ...
Series of Threads
4.1 Standard Coarse Pitch General Purpose and Mechanical Fastener Series M Profile 84.2 4.3 Preferred Sizes Standard Fine Pitch M Profile Screw Threads 8 84.4 ISO Metric Thread Series 8
Allowances and Tolerances 8
5.1 5.2 ISO System of Limits and Fits as Applied to Screw Threads Tolerance Grade 85.3 Tolerance Position 6 95.4 5.5 Allowance/Tolerance Formulas and Tables Selected Tolerance Classes 12 125.6 5.7 Length of Thread Engagement Circular Runout 13 135.8 Lead and Flank Angle Tolerances 135.9 13
6 Design Formulas and Tabulated Values for Allowances and
Tolerances6.1 General * 136.2 Rounding Procedure for Tabulated . Values 13
6.3 6.4 Allowances (Fundamental Deviations) Length of Thread Engagement 13 166.5 Crest Diameter Tolerances 16 166.6 Pitch Diameter Tolerances
7.1 General...... 197.2 Designation of Standard Screw Threads Designation for Thread Fit 19 207.4 7.3 Designation for Rounded Root External Thread 207.5 7.6 Designation of Special Threads Designation of Threads Having Modified Crests 20 207.7 Designation of Multiple Start Threads 21 227.8 Designation of Coated or Plated Threads
8
Dimensional Acmodation of Coating or Plating for 60 Deg Threads 22
8.1 Introduction 228.2 8.3 Dimensional Effects of Coating Material Limits for Coated Threads 22 228.4 8.5 ExternalThread With Allowance Available for Coating ExtemalThread With No Allowance for Coating 248.6 Electrodeposited Coatings Internal Threads 258.7 Other Considerations 25 26
6 Limits of Size 26
9.1 Standard Thread Series 269.2 9.3 Formulas for Calculating Limiting Dimensions for M Profile Screw Determination of Size Limits 26Threads 26 26
9.4 Examples of Calculations of Size Limits
10.1 Lead and Flank Angle Acceptance 35
Figures
2 I Basic M Thread Profile (ISO 68-1 Basic Profil) Intemal Thread Design M Profile With No Allowance (FundamentalDeviation) (Maximum Material Condition) 53 Extemal Thread Design M Profile With No Allowance (Fundamental Deviation) (Flanks at Maximum Material Condition) 54 5 M ProfileExtemalThread RootUpper andLower Limiting Profles for Metric Tolerance System for Screw Threads 676 7 Effects of Electrodeposited Coating on 60 deg Extermal Threads Ratio of Pitch Diameter Change to Thickness of Coating on 60 deg Threads 23 248 9 External ThreadLimiting M Thread Profle Tolerance Position g Internal Thread -Limiting M Profile Tolerance Position H 35 36
Tables
1 General Symbols Thread Data M Profle2
