Tools & Gear Drills Jobber

2013-WGS2 No.61 - 80 20 Piece Bright HSS Twist Set Bordo Wire Gauge Quick Silver M2-HSS Twist Drills. 118° Split Point (crankshaft point). Split point is self centering and reduces the need for end thrust. Friction at workpiece is reduced. 118° point angles are ideal for use in materials such as mild steel and cast iron. The 118° point creates easily controlled chips which are wide and thin. Bright Finish Twist Drills have no surface treatment and are supplied in the as-ground condition. These tools are suitable for general purpose use, particularly for non-ferrous applications. Gauge size drill calculations are generally made utilising a reference book or table. For example, to drill a hole which is 10 thou (thousandth of an inch = .001) bigger than a 1/8 bolt, the user must first work out that 1/8 is 125 thou, so the required hole size is 135 thou. Using a reference table establishes that you would need a number 29. Number drill bit gauge sizes are analogous to, but different from, American wire gauge. Number gauge is most commonly used from size 80 (the smallest) to size 1 (the largest) followed by letter gauge size A (the smallest) to size Z (the largest). Number gauge is actually defined down to size 97, but these smallest sizes are very rarely used.