examples of bits
Bits: detachable tools fitted with edges or abrasive parts; a router applies a rotating motion on them to mill a piece of work.
rounding-over bit 
Depending on the way it is positioned, it is a bit for rounding the edge of a piece of wood or for making a convex molding with a shoulder.
core box bit 
Bit usually used to mill grooves in wood in the shape of semicircles.
cove bit 
Bit used especially for concave moldings or for cutting articulating joints for a gate-leg table.
rabbet bit 
Bit for cutting an edge at right angles, used especially for making frames and for various cabinetmaking joints.
dovetail bit 
Bit for making cuts shaped like a dove’s tail, often used in joining drawers.
chamfer bit 
Bit for beveling edges at a 45° angle to create decorative edges and joints.