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Split Point Drill Question

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  • Split Point Drill Question

    I am reading an on line article on drill points by JOSEPH MAZOFF, apparently of Newman Tools Inc. It appears to be a very good piece on drill geometry.

    About 1/3 of the way down the page, just to the left of photos I and J he states, "The conventional split point (CSP) is highly productive but is limited since it cannot be utilized on drills beyond 1/2" dia." But he does not explain why this is the case. It would seem to me that the conventional split point could be ground on any drill over 1/8" or so in diameter. Or does he mean that it does not work well on larger drills for some reason.

    So does anyone know why he would say this? What is the concern?
    Paul A.

    Make it fit.
    You can't win and there is a penalty for trying!

  • #2
    Not sure what hes talking about, I never use the point on my drills over 1/2"

    (Allways drill a pilot first for a drill that big!)
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


    • #3
      If you have a large radial drill, you don't drill pilot holes........

      I also am not sure what he means, but it may be that the chisel point area becomes "unwieldy" to produce the point geometry on. He does say that the 4 facet split point "can be used on the largest of drills", as can the 6 facet, and modified split point. So it is something specifically about the CSP geometry.
      Last edited by J Tiers; 08-28-2010, 11:27 PM.

      Keep eye on ball.
      Hashim Khan


      • #4
        split drill

        I split drill points on all size drills. And it works for me. I have been a machinist for 58 years. And hardly ever drill with a smaller drill first. Unless the machine in under powered.

        None of the production shops I worked in drilled small drill first.
        Last edited by jimsehr; 09-01-2010, 12:04 AM.