Drill bit

A drill bit, comprising:

• a. a shank defining an axis,
• b. a spade cutter connected to the shank and having cutting edges extending generally radially of the said axis, and
• c. a lead point extending from the spade cutter formed by two edges that intersect the said axis, the lead point being provided with concave faces extending symmetrically of the axis and from edge to edge throughout a substantial portion of the point, so that the intersection of the point by a plane that is at a right angle to the said axis gives a cross-sectional shape in the form of a 4-sided plane figure, two sides of the figure being straight parallel lines defined by the aforementioned two edges and the other two sides being concave curves of generally circular-segmental form, so that a cutting edge is provided with a positive rake.