JPW JCT-3620, 3" 4-Bolt Chipping Hammer Round ShankDetails Jet 550620 Description JET Chipping Hammer are available in two heavy duty designs with multiple capabilities. The Four Bolt D handle model is designed for extra strength and provides better grip. The Saw Tooth handle model is engineered to dissipate the impact energy more efficiently. Each type has the option of round or hex shaped bushing shanks. Each model can accommodate standard oval collared chisels and retainers, making these heavy duty