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Large Concave Radius Milling

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  • Large Concave Radius Milling

    Does anyone have the article in the HSM:

    Large Concave Radius Milling
    Page Author Issue
    37 Hoff, Michael MW 2004 Feb-Mar

    Mine is missing and I really need the tecnique for a project here at home.

  • #2
    For HSM? There was a Jan-Feb issue and Mar-Apr issue, but no Feb-Mar issue. I looked and that article doesn't appear in either issue on page 37.


    • #3
      According to the article index, it's Machinist's Workshop 2004 Feb-Mar.

      I'm sure Neil would be happy to provide a copy for a modest fee.
      Try to make a living, not a killing. -- Utah Phillips
      Don't believe everything you know. -- Bumper sticker
      Everybody is ignorant, only on different subjects. -- Will Rogers
      There are lots of people who mistake their imagination for their memory. - Josh Billings
      Law of Logical Argument - Anything is possible if you don't know what you are talking about.
      Don't own anything you have to feed or paint. - Hood River Blackie


      • #4
        The best way to make concave surface milling is to set the head or rotary table at an angle useualy 45 degrees and rotate the part while using a fly cutter at the radius desired.


        • #5
          The article deals with machining a large diameter concave groove in a surface. Think very large ball nosed end mill.

          It gives a formula based on the diameter of the cutter and the radius of the cutter.

          Back issues should be available, and Marv Klotz may also have the calculations in his collection of formulas.
          Jim H.


          • #6
            I do indeed have a program for it on my page. Look for it under the name
            Regards, Marv

            Home Shop Freeware - Tools for People Who Build Things

            Location: LA, CA, USA


            • #7
              Wouldn't a B-port cherrying head work well for that?


              • #8
                I routinely make parts with large and small concave radius. I use a rotary table with an adapter I made. I can send you pictures of it working if you want.


                • #9
                  Just remember that all these techniques that involve tilting a large diameter cutter to produce an even larger concave radius DO NOT produce a true radius or circular segment. They actually cut an elliptical segment. The "radius" changes across the cut. In the days before CAD, ellipses were approximated by draftsmen with four circular segments and the approximation can look good. But a true ellipse superimposed over such a figure will show the differences.

                  If your requirement is for a true circular depression, it can be problematic. If any depression or a loose approximation of a circle is OK, then the techhique is OK. For the best approximation I would suggest a cutter that is at least twice the diameter as the width of the depression.
                  Paul A.
                  SE Texas

                  And if you look REAL close at an analog signal,
                  You will find that it has discrete steps.