Fastener Training Hex Head Cap Screw Hex Nuts Flat Washers Presented by Kevin Connolly Applications Engineer
[email protected] Fastener Terms and Abbreviations Below are three ways of describing the same fastener: 1. 1/4 – 20 UNC Class 2A x 1 Hex Head Cap Screw per ASME B18.2.1, Grade 5 per SAE J429, Zinc/Clear plated per ASTM B633 2. 1/4 - 20 x 1 Hex Cap Screw, Gr 5, Zn 3. 1/4 x 1 Hex Bolt, NC, 5, Z Metric Fasteners: M10 x 50 Hex Bolt, Property Class 8.8, Y What it means: They want a 10mm diameter hex head cap screw with a coarse thread (1.5mm) that is made from a property class 8.8 steel and is plated zinc with yellow chromate. The last three pages of this slide show contains a list of common abbreviations used when customers describe fasteners. Bolts Screws (must be assembled with a nut) (can be assembled by head or with a nut) Dimensions for Hex and Heavy Hex Cap Screws specified by ASME/ANSI B18.2.1 Grade 8 Grade A490 Regual Hex Head Heavy Hex Cap Screw Cap Screw Thread Length = 2 x Diameter + 1/4” (for lengths up to 6”) Screw Sizes Coarse and Fine Threads Decimal Closest Decimal Inch Size Equivalent Metric Size Conversion Coarse (UNC) Fine (UNF) 1/4 - 20 .250" M6 x 1.0 .236" - 28 x 0.75 5/16 - 18 .3125" M8 x 1.25 .315" - 24 x 1.0 3/8 - 16 .375" M10 x 1.5 .394" - 24 x 1.25 7/16 - 14 .4375" - 20 1/2 - 13 .500" M12 x 1.75 .472" - 20 x 1.25 9/16 - 12 .5625" M14 x 2.0 .551" - 18 x 1.5 5/8 - 11 .625" M16 x 2.0 .630" - 18 x 1.5 M18 x 2.5 .709" x 1.5 3/4 - 10 .750" - 16 M20 x 2.5 .787" x 1.5 7/8 - 9 .875" M22 x 2.5 .866" - 14 x 1.5 1 – 8 UNC .945" 1.000" M24 x 3.0 - 12 UNF x 2.0 - 14 UNS 1 1/8 - 7 1.125" - 12 M30 x 3.5 1.181" x 2.0 1 1/4 - 7 1.250" - 12 M36 x 4.0 1.417 x 3.0 Ultimate Tensile Strength (UTS) Force required to cause failure in cap screw in axial direction.