Square neck under the head is designed to keep the bolt from turning as the nut is tightened.
Zinc plated.
Tensile strength: 54,000 psi minimum.
Unified screw threads: UNC.
Diameter: 1/4″-20.
Length: 1-1/2″.
Made from low carbon steel. Bolt with a wide, countersunk flat head. Shallow conical bearing surface. Square neck under the head is designed to keep the