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Old 04-02-2012, 08:54 AM
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Dan308 Dan308 is offline
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Drilling Hard Steel help

Can someone help me out with drilling 3/16 holes in hard steel? I'm using tin coated bits with oil and slow speed and they are screeching and dull/breaking. My drill speed is slow, cutting oil is used. I heat to critical and cool the steel. then grind and shape. It's the small holes holes that are problems

I switched to cobalt drills. It made it easier but I can tell they won't last long. Any opinions on going to solid carbide spade bits?


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