Carriage bolts (round head with square neck) are commonly used in wood connections. The square neck under the round head will seat into the hole in the wood to prevent the head from turning. Because they are used with wood, carriage bolts are rarely high strength and virtually always supplied in a standard ASTM A307 specification.
Standard: ANSI/ASME B18.5/ DIN603
GRADE: A307,GR A,Gr2.
Material: carbon steel,Q195,A36
Size:from 1/4” to 1”, from 6mm to 24mm.
Surface finish:zinc plated, plain, black oxide, HDG
Packing: cartons with plywood pallet
Supply ability: 200tons per month
Assembly: normally with hex flange nut, with or without serration.