●Thread Type: UNC; Screw Thread: 1/4-20; Shoulder Size: 1-1/4" x 5/16"(L*D). ●Our shoulder bolts are made of alloy steel, with high strength, high toughness, wear-resistance, and corrosion resistance. ●Shoulder bolts, also called stripper bolts, are mechanical fasteners that can be screwed into one part and provide a free rotation pin joint connection with another part. ●The hex socket head can achieve high-torque tightening with limited clearance. ●The shoulder bolt widely used in automotive and mechanical applications. Ideal for punch and die assemblies.