The importance of correct bolt tightening cannot be over emphasized. In general the proper torque spec is usually around 65-70% of the failure torque rate. Torque for Flanged Hex Head and Tapered Socket Cap Bolts - use torque values specified by your equipment manufacturer. Thread Coeff Friction Preload (Kn) Property class Tightening Torque (Nm) Property class Min Breaking Torque; A1-50 A2-70 A4-80 A1-50 A2-70 A4-80 A1-50 A1-70 The torque figures quoted have been based on a theoretical bolt load equal to 85% of the proof load of the bolting material. Failure to set them correctly can lead to components becoming loose, bolts breaking or seals leaking. Suggested Starting Values. Metric Recommended Bolt Torque. Torque Tightening Values for Structural Steel Bolts Below is a list of the recommended tightening torques for 12.9 / 10.9 / 8.8 zinc plated finish bolts. Use of its content by anyone is the sole responsibility of that person and they assume all risk. Metric Recommended Bolt Torque. Metric Bolting Diameter Tensile Stress Area mm² Suggested Bolt Load KN.
Torque Settings. Approximate Torque Nm Grade 4.6 8.8 10.9 12.9 Manufacturers of bolts and/or machines establish torque specifications for their components and the nuts and bolts that hold them together. Determining the correct torque can however present problems. All values other than suggested torque amount are sourced directly from flange bolt charts and flange torque charts in the ASME B16.5 "Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard" (2017). Clamp loads estimated as 75% of proof load for specified bolts. Where the proof load is not quoted in the specification this has been taken as 95% of the yield stress. SizeUNRC Torque (N•m) Inch Metric Size Nominal Tightening Torque Nominal Tightening Torque Size (In-Pounds) Size (N•m) 4 5 6 8 10 1/4 516 3/8 1/2 5/8 Inch-Button Head Metric-Button Head 8-15 30 65 125 200 360 1000 1750 M3 x 0.5 M4 x 0.7 M5 x 0.8 M6 x 1 M8 x 1.25 M10 x 1.5 M12 x 1.75 Torque Settings Suggested Starting Values The below estimated torque calculations are only offered as a guide. Print this page . Torque for Dome Head and Countersunk Bolts - use the following torque guide. Print this page . ** Torque values for 1/4" and 5/16" sizes are in inch lb. Bolt torque specification charts Below is a list of bolt torques compiles from various machine tool manufacturers. The below estimated torque calculations are only offered as a guide. After fitting new parts we recommend you take your motorcycle for a … Bolt Diameter (mm) Recommended Torque (Nm) Class 8.8 After fitting new parts we recommend you take your motorcycle for a short test ride, riding with care. Maximum Recommended Tightening Torques Setting the correct torque on your torque wrench is critical to prevent under or over tightening of your bolts or nuts. Threads per inch 307A ASTM A307 Grade A SAE J429 Grade 5 SAE J429 Grade 8 F N L G 9 FNL Grade 9 Clamp Load (Lbs.) Torque Specifi cation Chart The following torque values are to be used on all fasteners unless otherwise specifi ed.