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Custom Drill Pointing Chicago

Bring efficiency to your resharpened drills at General Cutting Tools in Chicago: Iowa, Illinois, Wisconsin, Indiana, Michigan, and Minnesota.  The chisel edge is the least efficient operating surface element of the twist drill because it does not cut, but actually squeezes or extrudes the work material.  To improve the inefficient cutting conditions caused by the chisel edge, the point width is often reduced in a drill-point thinning operation.  Point thinning is particularly desirable on the larger size drills and also on those which become shorter in usage because the thickness of the web increases toward the shaft of the twist drill, thereby adding to the length of the chisel edge.  The extent of point thinning is limited by the minimum strength of the web needed to avoid splitting of the drill point under the influence of cutting forces.
Both sharpening operations – the relieved face grinding and the point thinning – should be carried out in special drill grinding machines or with twist drill grinding fixtures mounted on general-purpose tool grinding machines, designed to assure the essential accuracy of the required tool geometry.  Off-hand grinding may be used for the important web thinning when a special machine is not available; however, such operation requires skill and experience that we have here at General Cutting Tools in Chicago.
Improperly sharpened twist drills, e.g. those with unequal edge length or asymmetrical point angle, will tend to produce holes with poor diameter and directional control.
For deep holes and also drilling into stainless steel, titanium alloys, high temperature alloys, nickel alloys, very high strength materials and in some cases tools steels, split point grinding, resulting in a “crankshaft” type drill point, is recommended.  In positive rake cutting edges to the center of the drill, thereby greatly reducing the sharpening to maintain their increased drilling efficiency.

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