The Brownells Solid Carbide Drill Bit #28 (8-40) is a specially ground, single-flute, solid carbide drill ideally suited for use by the professional gun trade on hard receivers. It cuts a clean chip in hardest file steel, giving a true hole, and does not crumble out the steel, thus eliminating chatter. This precision tool is engineered for gunsmithing professionals who demand reliability when working with challenging materials.
The bit is 2 inches long to give quill clearance when using with scope and sight mounting jigs. When kept properly cleaned, it will not bind or break, and when properly fed, won’t work-harden the hole surface like a spade drill does, decreasing tap breakage. The drill is capable of drilling through hardened steels, making it invaluable for work on receivers that resist conventional tooling.
This bit should not be used in softer steels—use only after other drills have failed or when the hardness of steel is pre-known. Speed is approximately twice that of high-speed steel, with feed rate the same or slightly less. For armorers tackling the most demanding gunsmithing projects, the Brownells #28 (8-40) Solid Carbide Drill delivers professional-grade performance and precision.
