TAP WITH CHIP BREAKING CHAMFER
The tap comprises a shank portion and a threaded portion connected to the shank portion. The threaded portion includes a plurality of lands separated by flutes where each of the lands has threads formed thereon. Each of the plurality of lands including a chamfer formed at an end thereof where the chamfer is formed with a cutting edge and a heel edge. The cutting edge is formed with a first positive relief angle and the heel edge is formed with a second positive relief angle.
1 . A tap comprising:
a shank portion;
a threaded portion having a longitudinal axis is connected to the shank portion, said threaded portion including a plurality of lands separated by a flute;
each of said plurality of lands including a chamfer formed at an end thereof, said chamfer being formed with a cutting edge and a heel edge, said cutting edge formed with a first positive relief angle of less than 10 degrees and said heel edge formed with a second positive relief angle of less than 10 degrees.
2 . The tap of claim 1 further including a driving portion on said shank adapted to be releasably engaged by a turning tool.
3 . The tap of claim 1 wherein each of said lands have threads formed thereon.
4 . The tap of claim 1 wherein the cutting edge is located at a first radius from the longitudinal axis and said heel edge is located at a second radius from the longitudinal axis, said first radius being different than said second radius.
5 . The tap of claim 4 wherein each of said plurality of lands includes a center located at a third radius from said longitudinal axis, wherein said third radius is less than said first radius and second radius.
6 . The tap of claim 5 wherein the center of each of the lands is midway between the cutting edge and the heel edge.
7 . The tap of claim 5 wherein the radius of the plurality of lands decreases from said first radius to said third radius.
8 . The tap of claim 5 wherein the radius of the plurality of lands decreases from said second radius to said third radius.
9 . A method of tapping a part comprising:
providing a shank portion having a longitudinal axis and a threaded portion connected to the shank portion, said threaded portion including a plurality of lands separated by a flute where each of said plurality of lands including a chamfer formed at an end thereof, said chamfer being formed with a cutting edge and a heel edge, said cutting edge formed with a first positive relief angle and said heel edge formed with a second positive relief angle;
rotating said tap in a first direction such that said cutting edge is a leading edge; and
rotating said tap in a second direction such that said heel edge is the leading edge.
10 . A tap comprising:
a shank portion;
a threaded portion having a longitudinal axis is connected to the shank portion, said threaded portion including a plurality of lands separated by a flute;
each of said plurality of lands including a chamfer formed at an end thereof, said chamfer being formed with a cutting edge and a heel edge, said cutting edge formed with a first positive relief angle of 2 to 8 degrees and said heel edge formed with a second positive relief angle of 2 to 8 degrees; and
the cutting edge is located at a first radius from the longitudinal axis and said heel edge is located at a second radius from the longitudinal axis, and a center located at a third radius from said longitudinal axis, wherein said third radius is less than said first radius and second radius.
11 . The tap of claim 10 wherein the radius of the plurality of lands gradually decreases from said first radius to said third radius.
12 . The tap of claim 10 wherein the radius of the plurality of lands gradually decreases from said second radius to said third radius.