Things to add: -Lubrication is good and helps cool the bit also. If you don't have proper drilling lubricant, engine oil will do. Plan your work to avoid oveheating the bit (drill one hole at a time.) -HSS is Ok for most metals but blunts on stainless. For that you need a cobalt bit, low speed and high pressure (use a drill press if you can, step up drill bit size very gradually if you can't) -Any bit claiming to be "wood/metal" is likely an exceptionally poor metal drill bit that will blunt on anything harder than aluminium. It will work OK on wood but not as good as a proper wood bit. -If you're drilling more than one hole and struggling, the cost of a new bit will be repaid very quick in productivity -If you're drilling masonry with the hammer mode on a power drill and struggling, spend £70 on an SDS drill. They hit the bit while turning slowly, rather than spinning wildly with gentle taps. The difference is night and day. -Step drills have a max thickness capacity of about 2mm.
Things to add:
-Lubrication is good and helps cool the bit also. If you don't have proper drilling lubricant, engine oil will do. Plan your work to avoid oveheating the bit (drill one hole at a time.)
-HSS is Ok for most metals but blunts on stainless. For that you need a cobalt bit, low speed and high pressure (use a drill press if you can, step up drill bit size very gradually if you can't)
-Any bit claiming to be "wood/metal" is likely an exceptionally poor metal drill bit that will blunt on anything harder than aluminium. It will work OK on wood but not as good as a proper wood bit.
-If you're drilling more than one hole and struggling, the cost of a new bit will be repaid very quick in productivity
-If you're drilling masonry with the hammer mode on a power drill and struggling, spend £70 on an SDS drill. They hit the bit while turning slowly, rather than spinning wildly with gentle taps. The difference is night and day.
-Step drills have a max thickness capacity of about 2mm.
Why did I think you were going to show drill bits made of metal........