12 Uniform Shank Twist Drill Bits Great for Metalsmiths, Metal Working & Drilling. This is a new set of 12 uniform shank twist drill bits. Great for drilling holes. Swiss made. Can be used with all quick change or Jacobs chuck style handpieces. All have 3/32" (2.5 mm) shanks. These measure approximately 0.5 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6 mm (0.19", 0.23", 0.27", 0.31", 0.039", 0.043, 0.047", 0.051", 0.55", 0.059" and 0.062").