Silverline HSS Blacksmiths Drill Bit 14mm-25mm Steel Plastic Wood Aluminium Go to amazon.com Related posts How to buy the best 25 mm drill bit? FeatureLarge dia, high speed steel twist drill with reduced 12.5mm dia shanksUse on aluminium, steel, plastic, wood and non-ferrous metals. DescriptionLarge dia, high speed steel twist drill with reduced 12.5mm diameter shanks. Use on aluminium, steel, plastic, wood and non-ferrous metals.