Bowl Reversing Jaws 5" Diameter for Viper2 Chuck. Bowl reversing jaws, also known as Cole jaws or Flat jaws are most commonly used for remounting finished bowls to re-shape the outside or to remove unwanted spigots, recesses or jaw marks. The jaws are 120mm diameter when closed, 144mm diameter when opened.the work piece is held in place by 8 rubber coated fixings which can be fitted in 3 different positions on the jaws depending on the diameter required. For bowl diameters from 54mm up to 120mm. Please note max. rpm 600. Supplied with 2 sets of rubber coated fixings; 8 x 10mm diameter x 17mm long 8 x 10mm diameter x 13mm long.