Cutter heads with improved coupling
A modular cutter head having a holder defining a threaded receiver. The cutter head can be screwed into the threaded receiver. The cutter can comprise an elongated body portion having a cutting end and cutting edge and an elongated coupling portion spaced from the cutting end, with the coupling portion comprising a core and a plurality of generally helically-extending start threads disposed circumferentially about the core. The cutter head may also include a cutting end having a chip flute and an insert seat.
1. A cutter head, comprising:
an elongated body portion having a cutting end and an elongated coupling portion spaced from the cutting end; and
the coupling portion comprising:
a core; and
a plurality of generally helically-extending start threads disposed circumferentially about the core,
wherein each of the start threads defines a start index and wherein the start indexes are spaced apart from one another at substantially equal distances or radial/circumferential positions about the core,
wherein each of the start threads defines a lead, the lead being defined as an axial distance covered by one complete rotation of the start thread about a circumference of the coupling portion, and
wherein the lead of one of the start threads is different from the lead of another one of the start threads.
2. The cutter head of claim 1 , wherein the coupling portion comprises at least two start threads.
3. The cutter head of claim 1 , wherein the coupling portion comprises at least three start threads.
4. The cutter head of claim 1 , wherein the cutting end comprises a chip flute and at least one of a cutting edge and an insert seat; and
wherein each start thread further defines a pitch, a major diameter, a minor diameter, and a pitch diameter.
5. The cutter head of claim 4 , wherein the major diameter, minor diameter, and pitch diameter of at least one start thread remain constant in an axial direction away from the cutting end.
6. The cutter head of claim 4 , wherein at least one of the major diameter, minor diameter, and pitch diameter of at least one start thread decreases in an axial direction away from the cutting end.
7. The cutter head of claim 4 , wherein at least two of the major diameter, minor diameter, and pitch diameter of at least one start thread decreases in an axial direction away from the cutting end, forming a taper.
8. The cutter head of claim 1 , wherein a cross-section of the coupling portion taken along a plane perpendicular to an axis of rotation is substantially circular.
9. The cutter head of claim 1 , wherein a cross-section of the coupling portion taken along a plane perpendicular to an axis of rotation is non-circular.
10. The cutter head of claim 1 , wherein a cross-section of the core taken along a plane perpendicular to an axis of rotation is non-circular.
11. The cutter head of claim 1 , wherein a cross-section of the core taken along a plane perpendicular to an axis of rotation is substantially circular.
12. A tool, comprising:
a holder defining a threaded receiver and an opening configured to receive a modular cutter head, the threaded receiver including a threaded interior surface having at least one lead;
wherein the modular cutter head can be screwed into the threaded receiver, the modular cutter head comprising:
an elongated body portion having a cutting end and an elongated coupling portion spaced from the cutting end; and
the coupling portion comprising:
a core; and
a plurality of generally helically-extending start threads disposed circumferentially about the core,
wherein each of the start threads defines a start index and wherein the start indexes are spaced apart from one another at substantially equal distances or radial/circumferential positions about the core, and
wherein each of the start threads defines a lead, the lead being defined as an axial distance covered by one complete rotation of the start thread about a circumference of the coupling portion;
wherein the holder and the cutter head are configured to be directly coupled to one another, and
wherein at least one lead in the threaded receiver is different from the lead of at least one of the start threads of the coupling portion.
13. The tool of claim 12 , wherein the modular cutter head further comprises a cutting end including a chip flute and at least one of a cutting edge and an insert seat; and
wherein each start thread defines a first major diameter, a first minor diameter, and a first pitch diameter; and
wherein the threaded receiver includes a threaded interior surface having a second major diameter, a second minor diameter, and a second pitch diameter.
14. The tool of claim 13 , wherein the threaded interior surface comprises a number of start threads corresponding to the number of start threads disposed on the coupling portion of the modular cutter.
15. The tool of claim 14 , wherein at least one start thread on the cutter head and at least one start thread on the tool have a trapezoidal cross-sectional shape.
16. The tool of claim 15 , wherein the first major diameter and the second major diameter contact one another when the cutter head and the holder are coupled.
17. The tool of claim 13 , wherein the first major diameter, first minor diameter, and first pitch diameter of at least one start thread remains constant in an axial direction away from the cutting end, and wherein the second major diameter, second minor diameter, and second pitch diameter of the threaded receiver remain constant in an axial direction away from the opening.
18. The tool of claim 13 , wherein at least two of the first major diameter, first minor diameter, and first pitch diameter of at least one start thread decreases in an axial direction away from the cutting end, forming a first taper.
19. The tool of claim 18 , wherein at least two of the second major diameter, second minor diameter, and second pitch diameter of the threaded receiver decrease in an axial direction away from the opening, forming a second taper.
20. The tool of claim 19 , wherein the first taper is larger than the second taper, providing an interference fit when the coupling portion and the threaded receiver are coupled.
21. The tool of claim 12 , wherein:
the threaded receiver includes a threaded interior surface;
the threaded interior surface comprising a number of start threads corresponding to the number of start threads disposed on the coupling portion of the modular cutter;
in an assembled state, in which the holder and the cutter head are directly coupled to one another:
the threaded receiver and the coupling portion are coupled via threaded engagement of the start threads of the coupling portion and the start threads of the threaded interior surface; and
stress associated with the threaded engagement is redistributed away from the cutting end of the elongated body portion.
22. The cutter head of claim 1 , wherein each of the start threads covers at least one complete rotation about a circumference of the coupling portion.
23. The tool of claim 12 , wherein each of the start threads covers at least one complete rotation about a circumference of the coupling portion.