Threads and Materials - MSC Industrial Supply Co.

1 Threads and Materials 57 Threads and Materials Inch Series and Metric Threads Decarburization Limits Threads Per Inch H thread Height H From Root To Crest Min. H At Root Max. thread Pitch mm H thread Height mm H From Root To Crest Min. mm 80 72 64 56 48 44 40 36

2 32 28 24 20 18 16 14 13 12 11 10 9 8 7 6 5 4 58 Threads and Materials (continued)

3 thread Limiting Dimensions Inch Threads Class 3A through 1 , Class 2A 1 1/8 through 2 diameter Coarse Series Threads Nominal Screw Size Threads Per Inch UNRC Pitch Diameter Max. Min. Major Diameter Max. Min. Minor Diameter Min. #2 56 #3 48 #4 40 #5 40 #6 32 #8 32 #10 24 1/4 20 5/16 18 3/8 16 7/16 14 1/2 13 5/8 11 3/4 10 7/8 9 1 8 1 1/8 7 1 1/4 7 1 1/2 6 1 3/4 5 2 4 1/2 59 Threads and Materials (continued) thread Limiting Dimensions Inch Series Threads Fine Series Threads Nominal Screw Size Threads Per Inch UNRF Pitch Diameter Max.

4 Min. Major Diameter Max. Min. Minor Diameter Min. #2 64 #3 56 #4 48 #5 44 #6 40 #8 36 #10 32 1/4 28 5/16 24 3/8 24 7/16 20 1/2 20 5/8 18 3/4 16 7/8 14 1 12 1 1/8 12 1 1/4 12 1 1/2 12 1 3/4 2 60 Threads and Materials (continued) thread Limiting Dimensions Class 4g6g Metric Threads Nominal Diameter And thread Pitch Tolerance Class Allowance ES Major Diameter Max. Min. Pitch Diameter Max. Min. Minor Diameter (flat form) Max. Minor Diameter (rounded form) Min. Ref. 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g 4g6g Applicable Specifications: ASME , 61 Threads and Materials (continued) Limits for M Profile Minimum Rounded Root Radius Pitch Or thread SpacingRoot P Min.

5 Applicable Specifications: ASME , 62 Threads and Materials (continued) Tolerance Grade and Position Symbols for Classes of ISO Metric Threads external Threads Internal Threads Amount Tolerance Grade Tolerance Grade Major Diameter Pitch Diameter Tolerance Position (allowance) Minor Diameter Pitch Diameter Tolerance Position (allowance)

6 0 --- --- h --- --- H Small --- 3 --- --- 4 4 4 4 --- 5 5 5 6 6 g 6 6 G --- 7 7 7 8 8 8 8 --- g --- --- Large e --- ISO metric internal Threads are identified by the use of capital letters for the tolerance position.

7 ISO metric external Threads are identified by the use of lower case letters for the tolerance position. As an example: M6 x 4g6g indicates a metric thread form M , 6 mm nominal diameter. The fastener is externally threaded as noted by the lower case g . The tolerance position and grade of the major diameter is listed first 4g , followed by the tolerance position and grade of the pitch diameter- 6g . Standard Property Class socket screw products manufactured in the United States have 4g6g thread tolerances as the form most closely resembles the 3A thread form used on inch series socket products. When plating or coating of Threads is desired, a thread form with greater allowance should be selected. 63 Threads and Materials (continued) Diameter and thread Pitch Comparison Inch Series Size Nom.

8 Dia. In. Threads Per Inch Metric Size Dia. In. Pitch In mm Equiv. TPI (app.) Inch Series Size Nom. Dia. In. Threads Per Inch Metric Size Dia. In. Pitch In mm Equiv. TPI (app.) 85 127 1/4 20 28 #0 80 5/16 18 24 74 127 M8 20 25 #1 64 72 3/8 16 24 M2 64 101 M10 17 20 #2 56 64 7/16 14 20 56 74 M12 20 #3 48 56 1/2 13 20 #4 40 48 M14 2 17 M3 51 74 5/8 11 18 #5 40 44 M16 2 17 #6 32 40 M4 36 51 3/4 10

9 16 #8 32 36 M20 10 17 #10 24 32 M5 32 51 7/8 9 14 M6 25 34 M24 3 2 1 8 12 Research has shown that there are over 100 possible inch/metric fastener mismatches possible among commonly used sizes. Care must be taken not to mix the types together. 64 Inch and Metric Screw Threads (continued) Common Tap Drill Sizes Inch Series Threads Diameter Pitch (TPI) UNC Pitch (TPI) UNF Drill (in.) Decimal Wire, Letter Fractional #2 56 #50 64 #50 #3 48 #53 56 #53 #4 40 #43 48 #42 #5 40 #38 44 #37 #6 32 #36 40 #33 #8

10 32 #29 36 #29 #10 24 #25 32 #21 1/4 20 #6 28 7/32 5/16 18 G 24 I 3/8 16 5/16 24 Q 7/16 14 U 20 25/64 1/2 13 27/64 20 29/64 5/8 11 35/64 18 37/64 3/4 10 21/32 16