Tim Stevens | 14/08/2018 11:38:10 |
![]() 1779 forum posts 1 photos | Drill for this purpose are quite different from conventional twist drills. They rely on creating a lot of friction at the contact area, enough to heat to bright red, and so to soften the steel however hard it is. Then the corners of the pyramid push the hot metal aside, creating further heat, until you're through. Because of this they work best in a powerful column drill with lots of steady pressure. The resulting holes are not wonderfully round ... And don't try them to make holes in other materials such as Stellite or Carbide. Cheers, Tim Edited By Tim Stevens on 14/08/2018 11:38:50 |
Ian S C | 14/08/2018 12:17:48 |
![]() 7468 forum posts 230 photos | I have drilled a hole in hardened steel, and glass using a piece of steel tube and grinding paste (I think copper tube is the recommended metal). Slow speed in a drill press, and I made a spring loaded holder, just don't be in a hurry. Ian S C |
Howard Lewis | 14/08/2018 12:30:51 |
7227 forum posts 21 photos | Have never had much success with these "hard" drills, have several which have failed. If you are lucky, they will drill HSS, but note the word LUCKY! Howard
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