Bi-metal Hole Saw High Speed Bi-metal Edge Welded to Alloy Steel Back for Heavy Duty Cutting;4/6 variable Tooth; High Speed Steel, Bi-Metal Hole SawsDescription: 1. M3/M42 High Speed Bi-metal Edge Welded to Alloy Steel Back for Heavy Duty Cutting; 2. 4/6 variable Tooth; 3. Cutting Safely and Efficiently,the Best Way to Cut Large Holes, Clearing the Chips in Touch Materials; 4. Cutting Depth ...