Reversible hard jaws from Dillon Manufacturing Inc., which are suitable for ID and OD workholding, can reportedly decrease the time and cost of tool setups, yet still accurately grip and locate workpieces. The jaws hold a specific range of part sizes and are usually used for first operation workholding.

They are available in serrated, Acme Key, square key and tongue-and-groove styles to fit all brands of chucks. These single- or two-step jaws feature diamond-shaped serrations, which provide accurate gripping and parts locating.

They are manufactured of 8620 steel, case hardened, with ground locating surfaces and black-oxide coated for corrosion resistance. Dillon also offers custom made special or modified hard jaws.