The primary purpose of these step jaws is to grip in the contracting mode onto the base (foot) of footed bowls. The step sizes provide optimum gripping for three foot sizes with minimal crush damaged wood. The optimum step sizes are 42mm, 50mm and 64mm. Of course there is plenty of adjustment. There is also an expanding dovetail made for alternative recess gripping of bowls. Can hold bowls up to 300mm in diameter. The jaw expands into a recess between 77.5mm and 97.5mm diameter. When gripping onto the foot of a bowl the range is 41.5mm to 83.5mm diameter. These jaws will also hold square stock between 30mm and 66mm.