A modular drill includes a shank, a retaining pin, a cutting insert, and a locking pin. The shank includes a shank bore having an axial direction leading into the shank bore, and a locking pin opening. The retaining pin includes a retaining pin shaft axially movable positioned with the shank bore, the retaining pin shaft having a locking pin engagement surface. The retaining pin includes a retaining pin head having a retaining pin head engagement surface. The cutting insert includes a cutting insert passage for passing the retaining pin head therethrough; and a cutting insert cavity having a cutting insert engagement surface for engaging the retaining pin head engagement surface. The locking pin is for positioning within the locking pin opening and engaging with the locking pin engagement surface to force the retaining pin shaft to move further in the axial direction.

A modular drill is disclosed. The modular drill includes a tool shank extending along a rotational axis. The tool shank includes a shank top end and a shank bottom end along a rotational axis and includes a cam slot extending at least partially through a width of the tool shank. The modular drill includes a cutting head extending from a cutting head top surface to a cutting head bottom surface centered on the rotational axis. The cutting head includes a draw pin extending from the bottom surface of the cutting head along the rotational axis and a draw pin notch. The modular drill includes a clamping cam including a cam shaft contacting the draw pin notch.

The present invention provides a tool for drilling, the tool comprising two or more cutting edges and a web thinning, in which a thinning heel surface facing backward in a rotating direction of the tool is formed by a convex surface, and in which a thinning angle gradually becomes smaller from a leading end of the tool toward a base end thereof. A thinning rake surface of the web thinning may be shaped straight so as to extend from an area around a center of the tool and in a radial direction or a parallel direction thereto in a tool front view. A thinning rake surface may be shaped in a helix in an opposite direction to the rotating direction of the tool so as to extend from an area around a center of the tool and in a radial direction in a tool front view.