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  • #16
    You can make what watchmakers call a rose cutter or purchase a hollow mill. Somewhat like an endmill with an axial hole through it. Here's a link to a thread on another site I wrote on making small bolts. On the first page, there is a picture of a commercial hollow mill, and at the bottom is the one I made in use on a jewelers lathe.

    http://www.chaski.org/homemachinist/...hp?f=8&t=80867

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    • #17
      Originally posted by SGW View Post
      How long is it? I'd put the 3/16" rod in a collet with about 1/4" sticking out, turn that down, extend another 1/4" and turn that down, etc.
      Dpending what you need, you don't get a nice uniform and smooth finish that way. Box tool gives you uninterrupted cut from the start to finish, so there is no steps or any runout, plus its a lot faster.

      Which reminds me, I have to make such a tool for my work place, plenty of times I have required some odd size rod (like 9 mm) that just isn't readily available.
      Amount of experience is in direct proportion to the value of broken equipment.

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      • #18
        The hollow end mill idea sounds interesting....I'll try one out of drill rod. As usual, I'll spend more time making special tools to make parts than actually making the parts. That's my warped definition of fun.

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        • #19
          If you haven't already you may want to look at the drawing sets that Downriver Tools has for box tools among other things. The tools are cute as a button and he has good drawings and intructions. I've made box and balance tools as well as some others for a bed turret that can go on my lathe. Then with a stroke of insight machined a blank MT2 arbor to fit the shanks so I can pop any of the tools into the standard tailstock of my lathe. He's also got plans for a bed turret for small lathes that I'd have considered if I didn't already have one.
          .
          "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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          • #20
            Thanks for the heads-up, TGTool. I ordered the improved box tool plans. [I like the MT2 idea, mind if I steal it? ;-) ] Should save me a lot of design and trial-and-error time.

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            • #21
              Be my guest. I think I got the blank from Victor Machine which has the MT2 for $5.40 and you can hardly set up and machine a morse taper for that.
              .
              "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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              • #22
                Originally posted by Jaakko Fagerlund View Post
                Dpending what you need, you don't get a nice uniform and smooth finish that way.
                Yes, that can be a problem sometimes. It also doesn't work very well if the total overhang gets to be too great, although the free end can be supported in a tailstock bushing of some kind. The finish and uniformity can be dealt with by lapping. All things considered, a box tool, if you have one, may be a better choice. I merely offered the "nibble by degrees" option as a way of doing it when you don't have anything special.
                ----------
                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

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                • #23
                  Originally posted by bdarin View Post
                  The hollow end mill idea sounds interesting....I'll try one out of drill rod.

                  It will work better if you relieve the hole in the back for clearance so only a short distance right at the cutting edges is the finish diameter.
                  ----------
                  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

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                  • #24
                    What's wrong with buying a piece much closer to size & then having a shop that does centerless grinding bring it to size? Way easier than trying to turn down .187 to your .086 or so.
                    gvasale

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                    • #25
                      Originally posted by winchman View Post
                      What you need is a box tool. See post #2 here: http://www.homemodelenginemachinist....ing-tool-2773/
                      ...
                      Here's a direct link to the Chronos box tool referenced in the above link:

                      http://www.chronos.ltd.uk/acatalog/info_XC10____.html

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