In Reply to: Re: drill bits posted by Farmer Dan on December 22, 2018 at 14:06:46:
Yes, quality cobalt steel is the key to HSS drills. Carbide will be expensive, but not needed on softer material. Titanium is just the coating to provide longer tool life. It was originally used on CNC tools that required the use of coolant like soluble oil when used. They don't make solid titanium drills. The drill point is important for the type of material you are cutting too. For most applications, a standard 118° included angel drill point will work fine. For a more precision hole, carbide is best, and with a 135° included angle point, and when drilling hardened steel. A parabolic carbide drill with a 140° included angel drill point is even more precise, especially for deep holes. Carbide is extremely brittle and less forgiving than HSS. If the tool and the workpiece are not solidly secure, the carbide will chip or break. You should never use carbide in a hand held drill unit. It will almost surely chip or break. Always use carbide in a secure solid setup on a drill press. Sharpening carbide drills requires a different grinding wheel too.