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  • Any reason I can't use an old S/D drill for...

    Machinists,

    I'm attempting to make a collet extension for my Rotozip to add a bearing for more support.

    I am wondering if I can use an old, chipped Silver and Deming drill bit for this piece. I don't have any drill rod, but have some old bits.

    What is it going to take to cut this stuff? I have an OD toolpost grinder and carbide insert tooling.

    I plan to reduce the shank to .250 for the Rotozip collet, then up to .236 for the bearing, and then drill/ream for a .125 end mill. To hold the end mill I'm going to put two 10-32" setscrews opposite each other to clamp the endmill and eliminate vibration. I have a sensitive scale to balance the setscrews.

    What kind of tap do I need to use?

    Any help would be greatly appreciated.

    Regards,
    Jimno

  • #2
    Bump!

    I don't know if you are being ignored or just got missed.

    I can't help with your question, but I'm sure someone here can.

    Rgds
    Michael

    Australia

    Comment


    • #3
      Probably not. If its high speed steel you wont be able to machine it. If its a carbon steel drill you can probably anneal it.

      I wouldnt mess around. Just buy a short piece of 1144 or other alloy from Online Metals or some other source. Wont be much and you will save yourself a lot of frustration.

      As for your recipe for the extension you are asking for trouble. I am assuming a carbide end mill. A set screw will not hold on to one. At a minimum you will need to notch the shank of the mill to hold it.

      Instead look at using a ER11 collet.

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      • #4
        Dont know what I am missing but Macona's 'If its high speed steel you wont be able to machine it.' statement has me a bit puzzled as in the past I have machined HSS with no problems, drill end reduction for an extension springs to mind.
        I feel as if my HSS was the soft variety.

        Any answers.

        peter
        I have tools I don't know how to use!!

        Comment


        • #5
          Originally posted by ptjw7uk
          Dont know what I am missing but Macona's 'If its high speed steel you wont be able to machine it.' statement has me a bit puzzled as in the past I have machined HSS with no problems, drill end reduction for an extension springs to mind.
          I feel as if my HSS was the soft variety.

          Any answers.

          peter
          Drill shanks are usually either a different material, or left unhardened.
          Paul Compton
          www.morini-mania.co.uk
          http://www.youtube.com/user/EVguru

          Comment


          • #6
            Like EV Guru said the shanks are soft. Otherwise the chuck wouldnt have anything to grab into.

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            • #7
              i've had to turn down a S&D drill to get it to fit the tiny chuck on one of my drill motors in the past.

              even with a brand new carbide insert and a fairly powerful/rigid lathe, it was a royal PITA to do.

              i'd say avoid the headache and just buy a piece of material. get something that's leaded so it's easier to work...
              -paul

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              • #8
                Thanks for the bump, miker.

                I've decided not to mess with it. Seems I should be able to get better rigidity with a better high speed spindle. The RZ is ok, but not quite what I'm after. I did make an adapter that clamps to my quill and the side of the mill head so for the time being, I have a hss.

                Thanks again to all.

                Jimno

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