HOLE MAKING, THREADING, AND CHAMFERING TOOL

Abstract: A combined hole making, threading and chamfering tool (200, 300) with staggered thread cutting teeth (306, 308) doubles chip thickness and reduces side forces (less engagement) consequently allowing the feed rate to be increased and reducing thread milling time also reducing tool chatter providing a smoother surface finish in the thread.

Description: HOLE MAKING, THREADING, AND CHAMFERING TOOL CROSS-REFERENCE TO RELATED APPLICATION This application is based on United States Provisional Patent Application No. 60/003,634, filed September 12, 1995. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is in the field of cutting tools and processes for making a thread in or on a workpiece, and more particularly, to combined hole making, threading, and chamfering tools for making a hole, thread, and/or a thread in a workpiece. 2. The prior Art The prior art has employed various tool structures for cutting holes, threads, and/or chamfers in a work piece. Application and performance specifications of cutting tools influence manufacturing design and processes, such as in the high speed machining art. Problems with prior art cutting tool structures include limitations of their use and or inconsistent performance in the manufacturing process. For example, cutting conditions can cause the cutting too! to break, diminish its performance, deflect and produce poor results, and/or cause cutting edges to loose their effectiveness due to increased wear. U.S. Pat. No. 4,761,844, incorporated herein by reference, relates to a combined hole making and threading tool for drilling a hole in a workpiece on the inward fee of the tool and for threading the hole during retraction of the tool. The tool comprises a straight body with a drill point at the forward end, a shank at the rearward end and a thread form mill between the drill pont and the shank. U.S. Pat. No. 5,429,459, incorporated herein by reference, relates to a method of and apparatus for thread mill drilling. Figure 1 is a prior art combined hole making and threading tool 100 having a shank 102 at one end, a drill point 104 at the forward end, and a thread form mill 108 intermediate the drill point 104 and the shank 102. Thread-form mill 108 is provided with a multiplicity of thread-form cutters 112 and one or more flutes 110 extending from the drill point 104 throughout the thread form mill 108 for the purpose of chip removal. Each thread-form cutter 112 comprises a number of cutter segments 114a and 114b circumferentially aligned and are separated by the intervening flute 110. Each of the thread-form cutters 112 is of annular configuration and the number of cutters segments is preferably equal to or greater than the number of threads to be cut. During the thread cutting phase, the thread cutting segments 114a and 114b are laterally displaced into the wall of said hole. As the tool rotates, threads (not shown) are cut in the wall, generating cutting forces that act on the tool 100, including thread-form mill 108. The resulting thread-cutting forces can result in deflection in the too and diminish the thread tolerance. Under certain applications, such forces can limit the feed rate at which the tool can operate, and increase the thread cutting time, and/or cause the tool to break. What is needed is a cutting tool design that will overcome such prior art problems. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a side view of a prior art combined hole making and threading tool. Figure 2 is a side view of a combined hole making, threading and chamfering tool with staggered thread cutting teeth according to the present invention. Figure 3 is a side view of a combined hole making, threading and chamfering tool with cutting inserts including staggered thread cutting teeth. Figure 4 is a side view of a combined hole making, threading chamfering tool staggered thread cutting teeth and coolant passage according to another aspect of the present invention. Figure 5 A is side view of a combined hole making, threading chamfering tool with staggered thread cutting and an end mill hole making geometry. Figure 5 B is a side view of a combined hole making, threading chamfering tool with staggered thread cutting teeth and an inverted hole making geometry. DETAILED DESCRIPTION OF THE INVENTION Figure 2 is a side view of a combined hole making, threading and chamfering tool with staggered thread cutting teeth according to the present invention. Figure 2 illustrates a combined hole making and threading tool 200 having shank a 202 for engagement in a holder (not shown) of a machine system (not shown); a hole making means 204 for making a hole in a workpiece (not shown), said hole having a wall. Flute 208 extending from said shank 202 to said hole making means 204 forming a first land 210. First land 210 having a thread cutting edge 212 between said shank 202 and said hold making means 204. Another flute (not shown) extends from said shank 202 to said hole making means 204 forming a second land (not shown). Second having a thread cutting edge 214 between said shank 202 and said hole making means 204. Thread cutting edge 212 is offset by at least one pitch from thread cutting edge 214 to make staggered thread cutting teeth between shank 202 and hole making means 204. The staggered tooth doubles chip thickness and reduces side forces (less engagement), consequently allowing the feed rate to be increased and reducing the thread milling time, also reducing tool chatter providing a smoother surface finish in the thread. Staggered thread cutting teeth reduce number of engaged in a workpiece, during thread milling phase. Solid tungsten carbide is the popular material for these combination tools. High resultant side forces on the tool during the thread milling phase are caused by relatively high circumferentially engagement of the tool and a very low feed per tooth (chip thickness). A combined hole making, threading and chamfering tool with staggered thread cutting teeth doubles chip thickness and reduces side forces (less engagement) consequently allowing the feed rate to be increased and reducing thread milling time also reducing tool chatter providing a smoother surface finish in the thread. The chip removal v. force is a non-linear relationship. As the chip removal increases, the forces acting on the cutting edges increases at a lesser rate. The alternating (staggered) cutting teeth reduces the force acting on the thread milling portion of the cutting tool. This will reduce the force exerted on the thread portion of the cutting tool. Although each thread cutting tooth will remove additional workpiece material, the force acting on the tool does not increase by the same margin. Also, because the number of the thread cutting teeth is reduced, the forces acting on the thread portion had also been reduced. Chamfer 206 will chamfer the hole produce hole making 204. Chamfer cutting edge can also include forming a spot face. Coolant passages are discussed below for assisting in chip removal. Holder of the machine system call replace or augment the chamfer or coolant passage features in the cutting tool . Figure 3 is a side view of a combined hole making and threading tool with staggered thread cutting inserts according to another aspect of the present invention. Figure 3 shows a combined hole making, threading, and chamfering tool 300 having a shank 302 for engagement in a holder of a machine system (not shown) and a body 304 .extending from said shank 302. Body 304 having a first flute 310 and a corresponding cutting insert 306 attached by any suitable means, including screws 312 and 314. Body 304 further includes a second flute (not shown) having a corresponding cutting insert 308 attached by any suitable means, including screws (not shown). Body 304 may include, but is not required, one or more pockets (not shown) for receiving said cutting inserts 306 and 310. Cutting inserts 306 and 308 each include hole cutting edge (306c; 308c), thread cutting edge (306b; 308b), chamfering cutting edge (306a; 308a). Combined hole making, threading and chamfering tool 300 can have one or more flutes having a corresponding one or more cutting inserts. Each flute can have one or more corresponding cutting inserts, such as hole cutting insert, thread cutting insert or chamfering cutting insert. Flutes and corresponding cutting inserts can be disposed at any desirable angle, including helical and non-helical angles. Thread cutting inserts can have either standard or non- standard thread forms (e.g., staggered thread cutting teeth). Hole cutting inserts can also be used to form any desired geometry, including drill points, end mills, or inverted hole cutting edges. Figure 4 is a side view of a combined hole making and threading tool 400 with staggered thread cutting teeth and coolant passage according to another aspect of the present invention. According to an embodiment of the invention, a combined hole making and threading tool 400 includes means for supplying coolant to remove chips. Combined hole making and threading tool having a shank 402, a hole making means 406, staggered thread cutting teeth 404 disposed between said shank 402, chamfer cutting means 408 disposed between said shank and said staggered thread cutting teeth 404. Main coolant passage 408 and with branch passages 410a and 410b for supply of liquid under pressure to the hole making means for cooling and to aid in the chip removal. Figure 5 A is a side view of a combined hole making, threading chamfering tool with staggered thread cutting and an end mill hole making geometry. Figure 5 B is a side view of a combined hole making, threading chamfering tool with staggered thread cutting teeth and an inverted hole making geometry. The hole making means may be a drill point (e.g., 204), end mill 506, or any other hole cutting geometry, including inverted hole cutting edge 524. Cutting edges can be coated with materials improve performance and increase tool life, including applying wear resistant, corrosion and erosion resistant materials, including ultra hard materials. For example, diamond, diamond-like carbon, or CBN materials to the cutting edges for improved performance.

Claims: WHAT IS CLAIMED IS: 1. A combined hole making, threading and chamfering tool comprising: a shank for engagement in a holder of a machine system; a body extending from said shank, said body having at least one insert pocket for receiving at least one cutting insert; said cutting insert comprising a hole making cutting edge, a thread making cutting edge, a hole making cutting edge, and a chamfer cutting edge for producing a hole having a wall, threads in said wall, and a chamfer. 2. A cutting tool according to claim 1, further comprising: said at least one insert pocket having a helical angle for receiving at least one cutting inset having a corresponding helical angle. 3. A cutting tool according to claim 1, further comprising: a chamfer cutting means disposed between said shank and said hole making means. 4. A cutting tool according to claim 1, wherein: said holder having a coolant passage means. 5. A cutting tool according to claim 1, wherein: said holder having a coolant passage means and a chamfer cutting means. 6. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; staggered thread cutting teeth disposed between said shank and said hole making means. 7. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; at least one flute extending from said shank to said hole making means, said flute forming a land; said land having at least two staggered thread cutting teeth disposed axially at least two pitches apart for cutting threads in said hole. 8. A combined hole making and threading tool according to claim 1, wherein: said at least two staggered thread cutting teeth are disposed on different circumferential planes of said lands. 9. A combined hole making and threading tool according to claim 1 , wherein: said at least two staggered thread cutting teeth are offset (staggered) by at least one thread pitch. 10. A combined hole making and threading tool according to claim 1, wherein: said flute extends at a helical angle between said shank and said hole making means forming said land having a corresponding helical angle. 11. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; at least two flutes extending from said shank to said hole making means forming at least two lands; At least two staggered thread cutting teeth disposed on said lands so that a different circumferential plane defines each of said at least two staggered thread cutting teeth. 12. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; at least two flutes extending from said shank to said hole making means forming at least two lands; at least two staggered thread cutting teeth disposed on said lands so that a different circumferential plane defines each of said at least two staggered thread cutting teeth. 13. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; a first flute extending from said shank to said hole making means forming a first land, said first land having a thread cutting edge; a second flute extending from said shank to said hole making means forming a second land, said second land having another thread cutting edge offset by at least one pitch from said thread cutting edge disposed on said first land. 14. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; at least two flutes extending from said shank to said hole making means forming a corresponding at least two lands; at least one thread cutting edge corresponding at least two lands having a corresponding at least two said at least two lands having a thread cutting edge; a second flute extending from said shank to said hole making means forming a second land, said second land having another thread cutting edge offset by at least one pitch from said thread cutting edge disposed on said first land. 15. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall; at least two flutes extending from said shank to said hole making means forming at least two lands; at least two staggered thread cutting teeth disposed on said lands so that a different circumferential plane defines each of said at least two staggered thread cutting teeth. 16. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank at a first end, said shank adapted to be engaged for rotation and manipulation; a hole cutting means at an opposite end for making a hole in a workpiece, said hole having a wall; and at least two staggered thread cutting edges intermediate said first end and said opposite end for cutting threads in said wall, each said staggered thread cutting edge cuts a different groove in the wall of said hole. 17. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shank at a first end, said shank adapted to be engaged for rotation and manipulation; a hole cutting means at an opposite end for making a hole in a workpiece, said hole having a wall; and at least two staggered thread cutting edges intermediate said first end and said opposite end for cutting threads in said wall, each of said thread cutting edge cuts a distinct thread. 18. A combined hole making and threading tool with staggered thread cutting teeth comprising: a shaft located at a first end for engagement in a machine system; a hole making means located at an opposite end for making a hole in a workpiece, wherein said hole having a wall, at least two thread cutting profiles for cutting threads in said wall of said hole, said at least two thread cutting profiles separated by a flute for removing chips cut from the workpiece, said at least two thread cutting profiles have a plurality of staggered thread cutting teeth separated by at least one thread pitch and disposed on different circumferential planes along said at least two thread cutting profiles. 19. A combined hole making and threading tool with staggered thread cutting teeth for reducing the resulting cutting forces acting on the tool comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wal a thread making means disposed between said shank and said hole making means, said thread making means having staggered thread cutting edges (face) for cutting threads in or on a workpiece. 20. A combined hole making and threading tool with staggered thread cutting edges comprising: a shank for engagement in a holder of a machine system; a hole making means for making a hole in a workpiece, said hole having a wall a thread malting means disposed between said shank and said hole making means, said thread making means having staggered thread cutting teeth (face, edge) for cutting threads said hole.

Inventors: TURCHAN MANUEL C, TURCHAN, MANUEL, C.
Applicants: TURCHAN MANUEL C, TURCHAN, MANUEL, C.
Application year: 1996
Main classification: B23G5
IPC codes: B23G5