These inserts fit into the 50mm Axminster SK100 O'Donnell Dovetail Jaws. Held in place by four cap head screws they are relatively quick to fit. These inserts change the gripping range of the 50mm jaw to that of the 38mm O'Donnell jaw. The 38mm insert expands into a 50mm dovetail recess and contracts onto a 35mm dovetail or 28mm spigot. The Axminster chuck offers an external grip between 46mm and 60mm, internal dovetail 34mm to 51mm and spigot 24mm to 36mm. These can only be used in conjunction with the 50mm O'Donnell jaws. Made from stainless steel to protect against corrosion. These jaws are suitable for Clubman and Evolution SK100 chucks and the Evolution SK114 Chuck.