Shor lathe millgrain tools are used on a lathe with an SV-12 collect expander and collets to put a millgrain border on the edge of a ring or bracelet. Female tools are indented and leave a imprinted bead. Actual diameter is 1/4". The millgrain wheels are mounted on 1/8" (3.17 mm) square shanks, with an overall length of 2.5".