Crystalite's glass cones are perfect for smoothing out or grinding the inside lips on hand blown drinking glasses or goblets. They mount onto the threaded shaft of a horizontal bench grinder (you must supply the shaft size, thread count, and screw direction). Glass cones come in either a 45° (pictured above) or 60° (pictured below) format. The base measures 3" in diameter. You must supply your shaft size, thread count, and screw direction for us to process your order (ex. 5/8-11 left handed- The shaft size would be 5/8"; the threads per inch would be 11; and the screw direction would be to the left). (Four week lead time on these pieces!).