Twist drill and method for producing a twist drill which method includes forming a flute of a twist drill

Abstract

There is now provided a twist drill and a method for producing a twist drill which method includes forming a flute of a twist drill. The drill has drill material and a tip portion with a cutting lip. The drill has a land structure and a flute to remove chip residue. The land structure has a flute wall and a cutting edge structure that is disposed longitudinally along the flute wall. The cutting edge structure has a first portion at the drill tip portion and a second portion disposed away from the drill tip portion. The flute wall extends further into the land structure at the second portion of the cutting edge structure than at the tip portion to provide a greater amount of drill material at the tip portion than at the second portion of the cutting edge structure. The flute wall extends further into the land structure at the second portion of the cutting edge structure than at the tip portion to provide a greater flute volume per length at the second portion of the cutting edge structure than at the drill tip portion. The method provides for forming a drill with a grinding tool to form different angular transitions of the cutting edge structure.

1 - 22 . (canceled)  
   
   
       23 . A method of making a drill configured to drill a hole in an object, said drill comprising: a drill material; an axis of rotation about which said drill is configured to rotate during use; a tip portion comprising at least one main cutting edge; said at least one main cutting edge comprising a first main cutting edge; at least one land structure configured to form a flute to remove chip residue produced upon drilling; said at least one land structure comprising a first land structure comprising: a cutting edge structure and a flute wall extending from said cutting edge structure; said cutting edge structure being disposed to run longitudinally along at least a portion of said flute wall of said first land structure; said cutting edge structure comprising a first portion at or adjacent said tip portion and a second portion disposed away from said tip portion; and at least one of (a) and (b), wherein (a) and (b) are: 
 (a) said drill material comprising the same drill material from said first portion to said second portion of said cutting edge structure;    said flute wall being configured to extend further into said first land structure at said second portion of said cutting edge structure than into said first land structure at said first portion of said cutting edge structure to provide a greater amount of said drill material at said first portion than at said second portion of said cutting edge structure; and    said method comprising the steps of:    feeding said drill blank toward a grinding wheel;    forming said at least one rectilinear main cutting edge by rotating said grinding wheel and rectilinearly grinding said drill blank;    forming the portion of said flute at said first portion of said cutting edge by: 
 continuing feeding said drill blank toward said grinding wheel, and  
 moving said rotating grinding wheel in at least one dimension and adjusting the alignment of said grinding wheel with respect to said drill blank, and  
 continuing rotating said grinding wheel and grinding said drill blank and removing a first amount of drill material;  
   forming the portion of said flute at said second portion of said cutting edge by: 
 continuing feeding said drill blank toward said grinding wheel, and  
 moving said rotating grinding wheel in at least one dimension and adjusting the alignment of said grinding wheel with respect to said drill blank, and  
 continuing rotating said grinding wheel grinding said drill blank and removing a second amount of drill material being greater than said first amount to extend said flute wall further into said first land structure at said second portion of said cutting edge structure than into said first land structure at said first portion of said cutting edge structure to provide a greater amount of said drill material at said first portion of said cutting edge structure at or adjacent said tip portion than at said second portion of said cutting edge structure at a distance away from said tip portion; and  
   (b) said flute wall being configured to extend further into said first land structure at said second portion of said cutting edge structure than into said first land structure at said first portion of said cutting edge structure to provide a greater flute volume of said flute per length along said longitudinal axis at said second portion of said cutting edge structure than the flute volume of said flute per length along said longitudinal axis at said first portion of said cutting edge structure; and    said method comprising the steps of:    feeding said drill blank toward a grinding wheel;    forming said first main cutting edge by rotating said grinding wheel and grinding said drill blank;    forming the portion of said flute at said first portion of said cutting edge by: 
 continuing feeding said drill blank toward said grinding wheel, and  
 moving said grinding wheel in at least one dimension and adjusting the alignment of said grinding wheel with respect to said drill blank, and  
 continuing rotating said grinding wheel and grinding said drill blank and removing a first amount of drill material;  
   forming the portion of said flute at said second portion of said cutting edge by: 
 continuing feeding said drill blank toward said grinding wheel, and  
 moving said grinding wheel in at least one dimension and adjusting the alignment of said grinding wheel with respect to said drill blank, and  
 continuing rotating said grinding wheel and grinding said drill blank and removing a second amount of drill material being greater than said first amount to extend said flute wall further into said first land structure at said second portion of said cutting edge structure than into said first land structure at said first portion of said cutting edge structure to provide a greater flute volume of said flute per length along said longitudinal axis at said second portion of said cutting edge structure than the flute volume of said flute per length along said longitudinal axis at said first portion of said cutting edge structure.  
   
   
   
       24 . The method according to  claim 23 , wherein said first main cutting edge being disposed to run rectilinearly substantially toward the longitudinal axis of said drill, and said method further comprises the step of: 
 forming said first rectilinear main cutting edge by grinding said drill blank.    
   
   
       25 . The method according to  claim 24 , wherein each of said grinding wheel and said drill blank are configured to be moved with respect to one another, and said method further comprises the steps of: 
 moving said rotating grinding wheel in at least one dimension and moving said drill blank in at least one dimension to adjust the alignment of said rotating grinding wheel and said drill blank with respect to each other and grinding said drill blank.    
   
   
       26 . The method according to  claim 25 , wherein said grinding wheel is configured to be moved laterally in a plane substantially perpendicular to the rotational axis of said drill blank and to be pivoted in a plane substantially parallel to the rotational axis of said drill blank, and said method comprises at least one of the steps of: 
 moving said grinding wheel laterally in a plane substantially perpendicular to the rotational axis of said drill blank to adjust the alignment of said grinding wheel with respect to said drill blank; and    pivoting said grinding wheel in a plane substantially parallel to the rotational axis of said drill blank to adjust the alignment of said grinding wheel with respect to said drill blank and grinding said drill blank.    
   
   
       27 . The method according to  claim 26 , wherein said drill blank is configured to be moved in a feed direction and at least one of: in a rotational direction and in a direction perpendicular to said feed direction, and said method further comprises at least one of the steps of: 
 rotating said drill blank and grinding said drill blank; and    moving said drill blank in a direction perpendicular to the feed direction to further adjust the alignment of said grinding wheel and said drill blank with respect to each other and grinding said drill blank.    
   
   
       28 . The method according to  claim 27 , wherein said cutting edge structure has a plurality of rake angles at points along the length thereof, which rake angles are defined by a tangent of said flute wall perpendicular to the rotational axis of said drill and a radial line perpendicular to the rotational axis of said drill, wherein a rake angle at said first portion of said cutting edge structure is less than a rake angle at said second portion of said cutting edge structure, and said method further comprises the steps of: 
 grinding said drill blank at said first portion of said cutting edge structure and removing said first amount of drill material to form a first rake angle; and    grinding said drill blank at said second portion of said cutting edge structure and removing a second amount of drill material being greater than said first amount to form a second rake angle being greater than said first rake angle.    
   
   
       29 . The method according to  claim 28 , wherein said rake angles of said cutting edge structure increase along the length of said cutting edge structure in a direction away from said tip portion, and said method further comprises the steps of: 
 continuously grinding said drill blank with said grinding wheel and simultaneously continuously moving said drill blank and said grinding wheel to adjust the position of each with respect to each other to form said first main cutting edge, said flute and said cutting edge structure having a plurality of rake angles which increase along the length of said cutting edge structure in a direction away from said tip portion; and    performing said steps of moving at least one of said grinding wheel and said drill blank and grinding said drill blank to form at least another main cutting edge and flute.    
   
   
       30 . A method of making a twist drill; said twist drill having a longitudinal axis about which said drill is configured to rotate during use; said twist drill comprising: a plurality of main cutting edges being connected to one another by a chisel edge; said main cutting edges being disposed to run rectilinearly toward said chisel edge; a plurality of secondary cutting edges, each being disposed adjoining a corresponding one of said main cutting edges; a plurality of flutes being configured and disposed to permit removal of chips produced during drilling; each of said secondary cutting edges being disposed to run along a corresponding one of said flutes in the direction of the longitudinal axis of said drill; each of said flutes comprises a flute wall portion which extends from a corresponding secondary cutting edge substantially toward the longitudinal axis; each of said secondary cutting edges having a plurality of secondary rake angles (γ) at points along the length thereof, which secondary rake angles (γ) are defined by a tangent of said flute wall portion perpendicular to the longitudinal axis and a radial line perpendicular to the longitudinal axis, and which secondary rake angles (γ) increase along the length of said secondary cutting edges in a direction away from said tip portion; said method comprising the steps of: 
 forming a first rectilinear main cutting edge by grinding said drill blank;    forming a first flute and a first secondary cutting edge corresponding to said first main cutting edge by grinding said drill blank and removing increasing amounts of drill material along the length of the drill blank to form a first plurality of secondary rake angles (γ) which increase along the length of said first secondary cutting edge in a direction away from said tip portion; and    performing the above steps for at least one additional main cutting edge and its corresponding flute and secondary cutting edge.    
   
   
       31 . The method according to  claim 30 , wherein said step of forming a first flute and a first secondary cutting edge comprises continuously grinding a drill blank to form said first flute and said secondary cutting edge and thereby simultaneously said first plurality of secondary rake angles (γ) which increase along the length of said first secondary cutting edge in a direction away from said tip portion.  
   
   
       32 . The method according to  claim 31 , wherein each of a grinding wheel and the drill blank are configured to be moved with respect to one another, and said method further comprises the steps of: 
 moving said grinding wheel in at least one dimension and moving said drill blank in at least one dimension to adjust the alignment of said rotating grinding wheel and said drill blank with respect to each other and grinding said drill blank.    
   
   
       33 . The method according to  claim 32 , wherein said grinding wheel is configured to be moved laterally in a plane substantially perpendicular to the rotational axis of said drill blank and to be pivoted in a plane substantially parallel to the rotational axis of said drill blank, and said method comprises at least one of the steps of: 
 moving said grinding wheel laterally in a plane substantially perpendicular to the rotational axis of said drill blank to adjust the alignment of said grinding wheel with respect to said drill blank; and    pivoting said grinding wheel in a plane substantially parallel to the rotational axis of said drill blank to adjust the alignment of said grinding wheel with respect to said drill blank and grinding said drill blank.    
   
   
       34 . The method according to  claim 33 , wherein said drill blank is configured to be moved in a feed direction and at least one of: in a rotational direction and in a direction perpendicular to said feed direction, and said method further comprises at least one of the steps of: 
 rotating said drill blank and grinding said drill blank; and    moving said drill blank in a direction perpendicular to the feed direction to further adjust the alignment of said grinding wheel and said drill blank with respect to each other and grinding said drill blank.    
   
   
       35 . The method according to  claim 34 , wherein said rake angles of said cutting edge structure increase along the length of said cutting edge structure in a direction away from said tip portion, and said method further comprises the steps of: 
 continuously grinding said drill blank with said grinding wheel and simultaneously continuously moving said drill blank and said grinding wheel to adjust the position of each with respect to each other to form said first main cutting edge, said flute and said cutting edge structure having a plurality of rake angles which increase along the length of said cutting edge structure in a direction away from said tip portion; and    performing said steps of moving at least one of said grinding wheel and said drill blank and grinding said drill blank to form at least another main cutting edge and flute.    
   
   
       36 . The method according to  claim 35 , wherein said grinding wheel comprises a standard grinding wheel configured to grind a plurality of drill types.  
   
   
       37 . A method of making a twist drill; said twist drill having a longitudinal axis about which said drill is configured to rotate during use; said twist drill comprising: a plurality of main cutting edges being connected to one another by a chisel edge; said main cutting edges being disposed to run rectilinearly toward said chisel edge; a plurality of secondary cutting edges, each being disposed adjoining a corresponding one of said main cutting edges; a plurality of flutes being configured and disposed to permit removal of chips produced during drilling; each of said secondary cutting edges being disposed to run along a corresponding one of said flutes in the direction of the longitudinal axis of said drill; each of said flutes comprises a flute wall portion which extends from a corresponding secondary cutting edge substantially toward the longitudinal axis; each of said secondary cutting edges having a plurality of secondary rake angles (γ) at points along the length thereof, which secondary rake angles (γ) are defined by a tangent of said flute wall portion perpendicular to the longitudinal axis and a radial line perpendicular to the longitudinal axis, and which secondary rake angles (γ) increase along the length of said secondary cutting edges in a direction away from said tip portion; said method comprising the steps of: 
 forming a first rectilinear main cutting edge;    forming a first flute and a first secondary cutting edge corresponding to said first main cutting edge and thereby simultaneously forming a first plurality of secondary rake angles (γ) which increase along the length of said first secondary cutting edge in a direction away from said tip portion; and    performing the above steps for at least one additional main cutting edge and its corresponding flute and secondary cutting edge.    
   
   
       38 . The method according to  claim 37 , wherein said step of forming a first flute and a first secondary cutting edge comprises continuously grinding a drill blank to form said first flute and said secondary cutting edge and thereby simultaneously said first plurality of secondary rake angles (γ) which increase along the length of said first secondary cutting edge in a direction away from said tip portion.  
   
   
       39 . The method according to  claim 38 , wherein each of a grinding wheel and the drill are configured to be moved with respect to one another, and said method further comprises the steps of: 
 moving said grinding wheel in at least one dimension and moving said drill blank in at least one dimension to adjust the alignment of said rotating grinding wheel and said drill blank with respect to each other and grinding said drill blank.    
   
   
       40 . The method according to  claim 39 , wherein said grinding wheel comprises a standard grinding wheel configured to grind a plurality of drill types.  
   
   
       41 . The method according to  claim 37 , wherein said step of forming a first flute and a first secondary cutting edge comprises die-casting a twist drill comprising said first flute and said secondary cutting edge having said first plurality of secondary rake angles (γ) which increase along the length of said first secondary cutting edge in a direction away from said tip portion.