Think & Tinker, Ltd.
CNC router bits and carbide cutting tools with tutorials and technical guides

Tool Terms

Bit Diagram
Tip (Point Styles) Available in drill point, radical fish-point, shallow fish-tail, "V" point, and "Y" point.  See related article.
Flutes PreciseBits tools are available in 2,3, and 4 flute styles.  In general, the greater flute volume of two flute designs make them preferable in applications that demand aggressive debris removal .  Three flutes bits offer greater stiffness and freedom from resonant chatter at the cost of reduced flute volume and poor performance cutting materials that tend to "fluff up" when cut.. The length of the fluted portion of the tool is often referred to as the cutting length, Effective Flute Length (EFL) or Depth Of Cut (DOC). Since both "cutting length" and "Efective Flute Length" are subject to various interpretations between manufacturers, we use the less ambiguous "Depth OF Cut" or DOC in all of our product specifications.
Flute Extension Non-cutting portion of the flute that allows for additional bit plunging.
Shoulder Tapered section between the shank and the flute extension.  
Depth Ring Plastic collars pressed onto the shank that are used to precisely set the depth of cut.  Often used in systems with automatic tool changers.
Shank The length of the tool that inserts into the chuck or collet. 0.125", 0.250" and 0.375" dia. shank tools are currently available.
Shank Chamfer Makes bit loading easier and reduces collet wear.