Обший каталог Yamawa 2016 - 2017 - страница 852

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26. Center Drills products Center Drills are the tool for making center hole. Center Drills are also used for positioning before drilling, and for chamfering of the hole. of Description ■Names of each part Shank portion Countersink portion Drill diam. Drill portion diam. Drill length Shank Overall length ■Shape of center hole and center Type A (60°) Center hole & 60°center Type B (60°) Center hole & 60°center Type A (90°) Center hole & 90°center Type R Center hole & 60°center ■Advantage of Type B Center holes Avoid scar or distortion resulting from a blow Avoid roughness surface of work piece Avoid burrs around the hole Note : Advantage of Type B center holes : B type center drill protect the 60° conical bearing surface from scar or distortion resulting from a blow, roughness of workpiece surface or burrs around the hole. ■Advantage of Type R Center holes Angle of center hole is higher than Angle of center hole is lower than Center hole and center are misaligned. that of center. that of center. A type R type Technical Information Note : R type center hole stably holds the center. It also some of advantage of B type center hole. Technical-77 848