Now you can safety wire or pin any critical bolt quickly, easily. This inexpensive drill guide provides you the capability to drill any bolt size with a 1.5mm/1/16” size hole. Simply thread the bolt into the unit the required depth for your application. Next, drill your safety wire hole with no risk of misalignment. 2 Bolt Drilling Tool are available: - This is UNF/C accommodates 8-32, 10-32, 1/4-20, 1/4-28 & 5/16-24 bolts. - Also available  Metric does 6x1,8x1,8x1.25,10x1.25,10x1.5.