Starrett Holesaws. Constant Pitch up to 40mm Dual Pitch Professional Hole Saws 41mm and over are the latest development in multi use bi metal hole saws.  Featuring the smooth cutting action of our constant pitch hole saw, combined with aggressive material penetration and swarf clearance, Dual Pitch Professional will cut equally well on thin and thicker gauge materials.  This removes the need to carry a constant and a variable pitch hole saw. Advantages: · The complete multi purpose saw.  Dual Pitch Professional saws will cut a wide range of materials, irrespective of thickness. · New tooth geometry resulting in huge improvements in chip flow. · Smooth cut with minimal tendency to bite or snag when cutting thinner gauge materials. · Cutting depth 41mm (1 5/8?). · A range of general purpose and specialist kits are available, featuring the most popular sizes of saw.