Abstract A drill bit for drilling holes in metal sheets or panels in which the drill is of generally conical form having a series of cylindrical drill portions increasing progressively in diameter from the point end of the drill whereby a single drill may be employed to drill holes of various diameters within a given range. The drill has a single flute of generally right-angle form in cross section with the apex of the right angle extending generally along the axis of the bit. Each cylindrical portion has a beveled end connecting it with the next smaller cylindrical portion and this beveled end extends helically at a relatively small angle to provide the usual axial clearance and to limit the rate of feed of the drill into the work.
A drill bit for drilling holes of various selected diameters in metal sheets comprising a tapered drill body comprising a series of cylindrical portions increasing progressively in diameter from the small end of said body, beveled shoulders connecting the several cylindrical portions, a single flute extending along said drill body and having defining wall portions extending parallel to the axis of said drill body, said beveled shoulders extending helically at an angle of between two and five degrees to provide axial clearance and limit the rate of feed of said bit into the work, and said flute defining approximately a right angle with its apex generally coincident with the axis of said drill body, whereby approximately three-fourths of the periphery of each cylindrical portion is in continuous contact with the work.
Claim 2
Dependent Claim
131 words
A drill bit for drilling holes of various selected diameters in metal sheets comprising a tapered drill body comprising a series of cylindrical portions increasing progressively in diameter from the small end of said body, beveled shoulders connecting the several cylindrical portions, a single flute extending along said drill body and having defining wall portions extending parallel to the axis of said drill body, said beveled shoulders extending helically at an angle of between two and five degrees to provide axial clearance and limit the rate of feed of said bit into the work, and said flute defining approximately a right angle with its apex generally coincident with the axis of said drill body, whereby approximately three-fourths of the periphery of each cylindrical portion is in continuous contact with the work.