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Re: [GrizHFMinimill] How big of a drill for the grizz

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  • dswr@webtv.net
    If I need to bore a hole larger than 1/2 inch, and the work piece will not mount in my lathe... I drill a 1/2 inch starter hole with the work piece mounted on
    Message 1 of 6 , Feb 1, 2005
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      If I need to bore a hole larger than 1/2 inch, and the work piece will
      not mount in my lathe... I drill a 1/2 inch starter hole with the work
      piece mounted on the mill. Then I enlarge the hole, using a boring head.
      (homemade, i might add) 8-)

      Leo (pearland, tx)
    • jacoby01
      I m in the midst of a similar project - I ve got to bore a 1 3/8 hole in a piece of 1/2 Aluminum. Question: If I start out with a 1/2 hole, how heavy a cut
      Message 2 of 6 , Feb 1, 2005
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        I'm in the midst of a similar project - I've got to bore a 1 3/8"
        hole in a piece of 1/2" Aluminum. Question: If I start out with a
        1/2" hole, how heavy a cut can I take with a boring head? I've got
        an R8 shank boring head that takes 1/2" diameter boring bars - I
        haven't used this setup yet. Again, how heavy a cut can I take?
        Any suggestions on head speed (high range or low range?). And, I'm
        assuming that I should feed with the micro feed - Is this correct?

        The material is 6061 Aluminum.
      • Harvey White
        ... I take about 0.025 or so at the max, with a slow feed, you do not need to use the microfeed, but you do need to develop a feel for it. This will work for
        Message 3 of 6 , Feb 1, 2005
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          On Wed, 02 Feb 2005 00:31:26 -0000, you wrote:

          >
          >
          >I'm in the midst of a similar project - I've got to bore a 1 3/8"
          >hole in a piece of 1/2" Aluminum. Question: If I start out with a
          >1/2" hole, how heavy a cut can I take with a boring head?

          I take about 0.025 or so at the max, with a slow feed, you do not need
          to use the microfeed, but you do need to develop a feel for it. This
          will work for holes from about 0.500 to 0.800 in diameter, but past
          that, you will want to start taking off 0.010 at the max. It's a
          matter of how much load you want to put on the boring head.

          Your best bet would be to try to drill as much as possible. Do not do
          the trick of drilling holes around the circle, you will have an
          interrupted cut, which will put a lot of stress on the machine.

          >I've got
          >an R8 shank boring head that takes 1/2" diameter boring bars - I
          >haven't used this setup yet. Again, how heavy a cut can I take?
          >Any suggestions on head speed (high range or low range?). And, I'm
          >assuming that I should feed with the micro feed - Is this correct?

          Low range, about 10 to 11 o'clock on my mill. The limiting factor
          will be the depth of cut, and the amount of shake you get because you
          are swinging an off balance load.

          Tighten the Z axis gibs to reduce shake as needed, but you'll still
          need to feed slowly. The X and Y table motion must be locked.

          Harvey

          >
          >The material is 6061 Aluminum.
          >
          >
          >
          >
          >
          >
          >Yahoo! Groups Links
          >
          >
          >
          >




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        • jacoby01
          Thanks Harvey! This is exactly what I was looking for, I ll let you know how I make out. I might cheat a little and start out with a hole saw to get me close
          Message 4 of 6 , Feb 2, 2005
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            Thanks Harvey! This is exactly what I was looking for, I'll let you
            know how I make out. I might cheat a little and start out with a
            hole saw to get me close - I'll have to see what I've got on hand at
            the shop, and if the hole saw will handle the job. Again, thanks
            for the speed and feed information. Bob
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