Starrett Fast Cut Bi-Metal Holesaws provide a smoother, faster cut on a wide range of materials, when compared to the previous constant pitch saw. Improved tooth material and 5.5 TPI/25mm tooth form for enhanced heat and wear resistance and greater product life. Specifically suited to cutting stainless and mild steel sheet, they will also cut through tubes with a wall thickness of up to 3mm (1/8in). Cutting Depth: 41mm. Starrett FCH0400 Fast Cut Bi Metal Holesaw has the following specification: Diameter: 102mm (4in).