1. A 45° corner Chamfer improves cutting edge strength, so these end mills last longer than standard square end mills when milling hard material; however they do not create as sharp of a corner

2. KIPA Adjustable Magnetic Gauge Tool Camber Castor Strut Wheel Alignment Tool for Truck Car RV Tire Repair, New Top Strong Magnetic Absorb, Ingenious Design, Practical (Square End Mounting) 4.4 out of 5 stars 778

3. Definition of Battledore 1 a : a beetle or bat that is used in washing or smoothing clothes b : a tool with a long flat blade with a square end that is used in glassworking to flatten the bottoms of vessels