A Morse taper is a standard system for securely attaching drill bit tools to the drill press machine spindle. During rotation, the part is held in place by friction of tapered shanks against the hollow spindle that holds the tool. Attachments with a tapered shank can be fitted and removed quickly and easily so the user can have a greater variety of bit sizes available.
There are many families of drill bits in existence that are distinguished from other tapered drill bits in the degree that they taper from wide to small end. Morse tapers will narrow approximately 5/8 inch (1.5 centimeters) per foot (30.4 centimeters). Each of the eight sizes is identified by a number between 0 and 7, with the most commonly used being size 2, or 2MT. Small numbers correspond to smaller diameter parts and large numbers to larger diameters.
Drill press accessories have a tang, or prong, end that allows the bit to fit snugly into the slot in the spindle of the machine. The taper positions and holds the bit in place with friction. During light drilling, friction is adequate to hold the tool in place. Heavier drilling with stronger forces may cause the bit to spin in the hole instead of drilling.
To secure the bit more tightly, the tang end of the Morse taper shank fits into a slot in the socket. This will keep the drill bit spinning even when the drill encounters heavy resistance. Once the drill bit is fitted into the socket of the drill press by hand, it is turned until the tang clicks into place. The entire assembly is then pressed against a block of wood or metal to secure it tightly into the socket so it does not spin during use. The bit may also be tapped with a brass or lead hammer until it fits tightly.
Despite the variety of sizes, sometimes a longer or wider diameter shank is needed to fit the accessory into the machine. Socket extensions will increase the length of the bit. Sleeve adaptors add width to the drill bit so it will fit into a larger socket.
The Morse taper was invented by Stephen A. Morse, a machinist in the 1860s. His taper was adopted as ISO 296 standard by the International Organization for Standardization and as DIN228-1 by the German Institute for Standardization. A Morse taper will fit antique drill presses as well as a modern drill press.
