Drill bits are the cutting tools of drilling machines. They can be made in any size to order, but standards organizations have defined sets of sizes that are produced routinely by drill bit manufactur
Metric drill set, 1.0–6.0 mm by 0.1 mm, jobber length. The case that holds them in an indexed order (by size), via a graduated series of holes, is called a drill index.
Fractional drill bit set by Craftsman
11⁄32-inch drills: long-series Morse, plain Morse, jobber
A machine taper is a system for securing cutting tools, workholders or toolholders in the spindle of a machine tool or power tool. A male member of conical form fits into the female socket, which has
Drill bit sizes
…ANSI B94.11M-1979 sets size standards for jobber-length straight-shank twist drill bits from 1⁄64 inch through 1 inch in 1⁄64-inch increments. For Morse taper-shank drill bits, the standard continues in 1⁄64-inch increments up to 1+3⁄4 inches, then 1⁄32-inch increments up to 2+1⁄4 inches, 1⁄16-inch increments…
Drill chucks mounted by Jacobs tapers onto arbors with Morse tapers for the spindle.
Spindle nose on a lathe headstock. The small female taper is a Morse taper to take a lathe center or a tool such as a twist drill. The large male taper takes a lathe chuck, which is retained by the large nut.
Example of Self-Holding Taper; Brown & Sharpe (BS) #7 (left) and three BS9 Shank Milling Cutters (Right) without Provision for Drawbar
Morse taper No. 2 (MT2) with a Tang