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Hard to drill holes.

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  • Hard to drill holes.

    Hi, if I have a hole to drill that I can't get the chuck within 4" of for a spot drill or short pilot hole bit, what is the best method to accurately drill a 1/2" deep hole 1/2" wide in cast iron?
    (Accurate location, Diameter isent so important)
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

  • #2
    1/2" split point drill in 1/2" collet

    or drill guide bushing

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    • #3
      6" long center drill to spot.....1/2" body.....

      http://metalworking.mscdirect.com/CG...PMPXNO=2044236
      Last edited by Uncle O; 12-14-2009, 06:57 AM.

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      • #4
        Long center drills

        Originally posted by Uncle O
        6" long center drill to spot.....1/2" body.....

        http://metalworking.mscdirect.com/CG...PMPXNO=2044236
        I second that motion!!! I have several of these and they come in handy more times than I can count.
        Jim (KB4IVH)

        Only fools abuse their tools.

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        • #5
          Make an extension to hold a centre drill. It can be something like this tap holder with a longer reach.

          Free software for calculating bolt circles and similar: Click Here

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          • #6
            Originally posted by Evan
            Make an extension to hold a centre drill. It can be something like this tap holder with a longer reach.

            That looks serviceable.

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            • #7
              Hmm that sounds like a good idea.. 5" long cold rolled bar, set screw, little lathe time.. To bad I just took apart my tailstock.. doh.
              Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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              • #8
                To bad I just took apart my tailstock.. doh.
                So what? Take a short piece of round like in my pic and drill it lengthwise approximately on center in the drill press. Chuck up a length of round in the lathe and turn a 1/2" long boss to a press fit in the hole. Presto, concentric hole. You can clean up the OD concentricity if it bothers you but it isn't necessary.
                Free software for calculating bolt circles and similar: Click Here

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                • #9
                  Originally posted by Evan
                  So what? Take a short piece of round like in my pic and drill it lengthwise approximately on center in the drill press. Chuck up a length of round in the lathe and turn a 1/2" long boss to a press fit in the hole. Presto, concentric hole. You can clean up the OD concentricity if it bothers you but it isn't necessary.
                  At this rate, why not just buy a long drill and save yourself the two extra connection points.

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                  • #10
                    What bean bag said. That's what I'd do. Make sure it's a split point though.

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                    • #11
                      That's fine if you don't need it right away. You also have to factor in the cost to buy it plus getting it to your shop. Shipping/gasoline aren't cheap.
                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        This just a small variation on the ideas- use a piece of known round and straight 1/2 inch rod, chuck in lathe and use a steady rest to control the outboard end. Spot and drill for a center drill bit. Drill and tap for a setscrew, and grind a little flat on the center drill where the setscrew will touch it.
                        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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