Method for manufacturing treatment device and treatment device

Abstract

A tapered cutting edge portion and a continuous raise portion from the tapered cutting edge portion are ground in an edge portion of a straight grinding raw material so that an eccentricity is not generated. In a method for grinding a treatment device, one end portion of a tapered grinding raw material is inserted between a grinding surface of a grindstone and a pressing surface of a press block, and finishing surfaces opposite each other while having a predetermined dimension, shape, and angle are ground so that a direction in which abrasive grains of the grindstone run corresponds to a direction of a shaft center. At this point, before the finishing surfaces are ground in the predetermined dimension, shape, and angle which are previously set corresponding to an objective reamer, pre-grinding is performed while a necessary finishing margin with respect to at least one of the surfaces, and then finishing grinding is performed to the other surface.

1 - 6 . (canceled) 
   
   
       7 . A grinding method in which an eccentricity is not generated when a tapered cutting edge portion and a continuous raised portion from the cutting edge portion are ground in an edge portion of a straight grinding raw material having a central longitudinal axis, and at least one pair of opposite surfaces comprising a first and second surface, and an amount of grinding is detected in each grinding step, the steps comprising:
 (a) grasping one end portion of the raw material in a chuck and another end portion between a grinding surface of a grindstone and a press block;   (b) initiating a first grinding on a first surface of the raw material so that a direction in which abrasive grains of the grindstone run corresponds to an axial longitudinal direction of the raw material, and discontinuing the first grinding before said one surface is ground to a depth corresponding to a predetermined final first surface having a predetermined dimension, shape, and angle, thereby leaving a first finishing margin of unground raw material extending from a final depth of material of said first final surface to be formed;   (c) rotating the raw material 180° in the chuck and then initiating a second grinding on a second surface of the raw material, while holding said another end portion of the raw material between a grinding surface of a grindstone and a press block, and discontinuing the second grinding before said second surface is ground to a depth corresponding to a predetermined final second surface having a predetermined dimension, shape, and angle, thereby leaving a second finishing margin of unground raw material extending from a final depth of material of said second final surface to be formed;   (d) rotating the raw material 180° in the chuck and repeating the step (b) and/or (c) until the each surfaces are ground to final surfaces having a predetermined dimension, shape, and angle.   
   
   
       8 . The grinding method of  claim 7 , wherein after the first grinding is performed for the first surface, the second surface is ground to have a predetermined dimension, shape, and angle, followed by grinding the first surface to have a predetermined dimension, shape, and angle. 
   
   
       9 . The grinding method of  claim 7 , wherein, in step (c), a second finishing margin is left on the another end portion of the raw material, said second finishing margin then being removed in a subsequent fourth grinding step after the grinding step of step (d) on the first finishing margin is performed, said fourth grinding continuing until distances between a central longitudinal axis of the raw material and resultant ground surfaces are all equal. 
   
   
       10 . A method for manufacturing a treatment device using the grinding method of  claim 7 , further comprising twisting the raw material about its central longitudinal axis whereby to form spiral grooves. 
   
   
       11 . A treatment device formed from a straight thin bar-shaped raw material having a central longitudinal axis and at least one pair of opposite surfaces comprising a first surface and a second surface, in which the first and second surfaces are ground to have a predetermined dimension, shape, and angle, without generating an eccentricity, said treatment device being manufactured by the steps comprising:
 (a) grasping an end portion of the thin bar-shaped raw material in a chuck and another end portion between a grinding surface of a grindstone and a press block;   (b) initiating a first grinding on a first surface of the thin bar-shaped raw material so that a direction in which abrasive grains of the grindstone run corresponds to an axial longitudinal direction of the thin bar-shaped raw material, and discontinuing the first grinding before said first surface is ground to a depth corresponding to a final surface having a predetermined dimension, shape, and angle, thereby leaving a first finishing margin of unground raw material extending from a final depth of material of said first final surface to be formed;   (c) rotating the thin bar-shaped raw material 180° in the chuck and then initiating a second grinding on a second surface of the thin bar-shaped raw material opposite said first surface while holding said another end portion of the thin bar-shaped raw material between a grinding surface of a grindstone and a press block, an discontinuing the second grinding before said second surface is ground to a depth corresponding to a predetermined final second surface having a predetermined dimension, shape, and angle, thereby leaving a second finishing margin of unground raw material extending from a final depth of material of said second final surface to be formed;   (d) rotating the thin bar-shaped raw material 180° in the chuck and repeating the step (b) and/or (c) until the each surfaces are ground to final surfaces having a predetermined dimension, shape, and angle.   
   
   
       12 . The treatment device of  claim 11 , wherein after the grinding step (d) the thin bar-shaped raw material is twisted about its central longitudinal axis to form spiral grooves. 
   
   
       13 . The method for manufacturing a treatment device of  claim 8 , further comprising twisting the thin bar-shaped raw material along its central longitudinal axis, thereby forming spiral grooves therein. 
   
   
       14 . The method for manufacturing a treatment device of  claim 9 , further comprising twisting the thin bar-shaped raw material along its central longitudinal axis, thereby forming spiral grooves therein.