Trend 3/21 x 1/4 HSS Two Flute Cutter 6.3 x 28mmTrend HSS Two Flute Straight Cutters are made from a single piece of High Speed Steel, ground with a very fine edge. Generally HSS cutters are slightly less expensive than their TC grades, but can be more suitable for certain applications. Suitable for general grooving and rebating. Suitable for non abrasive materials, but will give a superior finish in soft timbers. Specification D: 6. 3mm (1 4in) C: 28mm OL: 59mm Shank Diameter: 1 4in