Origin: ImportedAlso know as a coach bolt or round head square neck bolt, carriage bolts are intended for use through iron strengthening plates on either side of a wooden beamIt is commonplace to use them into bare timberCarriage bolts have a squared section under their round head that grip to prevent rotationFinish as per ASTM F2329Body Diameter: 0.272 - 0.324 Inch Diameter: 5/16 Inch Finish: Hot Dipped Galvanized Grade: A Head Diameter: 0.688 - 0.719 Inch Head Height: 0.156 - 0.176 Inch Head Style: Round Item: Carriage Bolt Length: 2-1/2 Inch Material: Low Carbon Steel Measurement: Inch Origin: Imported Specification: ASME/ANSI B18.5,ASTM A307 Square Depth: 0.156 - 0.187 Inch Square Width: 0.307 - 0.324 Inch Thread Length: 2-1/2 Inch Thread Type: Coarse Threads Per Inch: 18 Type: Full Threaded