Blunt drills and frayed holes are often the result of unsuitable drill selection. Although many drills (such as twist drills) are visually similar, they are not easily interchangeable. Their functioning can be completely different. Further differences exist in material, cut, shank and twist. Knowing which drill bit is best and when, is therefore important not least in order to work high quality and profitable. Part 1 of our drilling series introduces the most common types of drills and their applications.
HSS is an abbreviation for High Speed Steel and refers to a high-alloyed tool steel. Up to four times higher cutting speeds are possible with HSS compared to ordinary tool steel, as the material retains its hardness even at high temperatures (up to approx. 600 ° C). Today, HSS drills have almost completely replaced conventional tool steel drills with machinability because of these properties.
SDS binding stands for ‘Special Direct System’ and is a profiled connector on a drill stem. It enables a quick drill change.
In Tool and Die Service, the classic HSS drills with SDS bond according to DIN 338 (High Speed Steel) in many different qualities are used. The drills made of high-speed steel are characterized by high wear resistance, tempering resistance and hot hardness. So they are not only up to the stresses of everyday work, but guarantee more accurate work and long-term cost savings.
Which criteria should be considered in the selection? Whether a drill is coated or not says something about its quality. High quality drills are coated, their tips are often colored. Such coatings (eg of titanium) can increase the service life of the drills considerably. At the same time they are suitable for high-hardness materials that are no longer up to standard HSS drills. High-hardness materials include, for example, metals, diamonds or cubic boron nitride.
Titanium and stainless steel for higher tensile strength as shown in Tool and Die Service. In addition, titanium-alloyed drills or drills made of stainless steel offer significantly higher tensile strengths and must be reground much less frequently. For frequent drilling they are absolutely recommendable. Their higher price, which results from the higher quality materials, is certainly worthwhile in terms of efficiency and longevity.
Even HSS drills eventually reach their performance limits. For professional drilling especially in high-hardness materials or drill holes with larger diameters (such as for sockets) particularly powerful drilling tools are in demand. Whether dry or wet drilling: There are suitable diamond drills for both methods.
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