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Poor Mans Dovetail---

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  • Poor Mans Dovetail---

    I have been thinking about making a quick change toolpost for my lathe. This of course requires a dovetail milling cutter. I just priced a dove tail milling cutter yesterday, and it would cost $70. Last night, as I lay in bed fighting my chronic insomnia, I got thinking about alternate ways to come up with a dovetail. I want the end result to look like this,
    Brian Rupnow

  • #2
    And of course, it would disassemble into two peices which look like this---
    Brian Rupnow

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    • #3
      And---having far more time than money these days, I thought---Why couldn't I make it out of individual peices as shown, and use dowel pins and 1/4" SHCS to assemble the peices.
      Brian Rupnow

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      • #4
        I think it would certainly work at the expense of some rigidity.
        Peter - novice home machinist, modern motorcycle enthusiast.

        Denford Viceroy 280 Synchro (11 x 24)
        Herbert 0V adapted to R8 by 'Sir John'.
        Monarch 10EE 1942

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        • #5
          I don't think it would hurt ridgity all that much. I think with dowels and good fasteners it will be plenty stout.

          Many guys also just make a dovetail cutting tool from scratch and use a single carbide insert.

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          • #6
            Brian nice design and should work well, however to save yourself a lot of work take a look at this:

            http://www.dogpatch.com/bobp/shop/dovetail.htm

            Michael

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            • #7
              Nice design Brian,

              Looks like something a fella could knock out in a hurry if he needed a special kind of tool holder.

              What software did you use to draw that rendering in?

              Tim

              PS It just occurred to me that a fella could mill some long lengths (12"-18") of the dovetail material while he had it set up, store it, then cut and drill it when needed
              Last edited by tmc_31; 08-15-2009, 10:49 AM.

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              • #8
                Originally posted by tmc_31
                Nice design Brian,

                Looks like something a fella could knock out in a hurry if he needed a special kind of tool holder.

                What software did you use to draw that rendering in?

                Tim
                All my design work is in Solidworks. (Click on my web address at the bottom of this post to see more.)---Brian
                Brian Rupnow

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                • #9
                  Originally posted by Michael Hall
                  Brian nice design and should work well, however to save yourself a lot of work take a look at this:

                  http://www.dogpatch.com/bobp/shop/dovetail.htm

                  Michael
                  Thats a good idea Michael, but my machine is a small Chinese mill with MT2 taper in the spindle, and won't take a very big cutter.---Brian
                  Brian Rupnow

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                  • #10
                    Won't take a very big cutter or won't take a very big cut with a very big cutter. I have a mini-mill and have used flycutters with it. The trouble with a single-tooth cutter is the hammering you get. Bob Warfield and others here have made dovetail cutters. The secret is to cut the pocket at a compound angle as I recall....such that the cutter both leans back relative to the spindle and "in" toward the center...giving positive rake in two axes. This helps the cutter shear rather than chop.

                    Paul
                    Paul Carpenter
                    Mapleton, IL

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                    • #11
                      Your design will work fine, Brian. A friend of mine came up with the same rough idea, and I cranked it out for the toolholder. Didn't have any flat head Allens on hand, so I used what I had with a dose of 271 Loctite on the screws as well as the back of the dovetail. No chatter. Works great.

                      Wayne

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                      • #12
                        I don't see why more home made tool holders don't use the 90deg v technique
                        that are on the Clausing Metosa lathes at school. I have a pix of the holders,
                        but not of the post, handy but havn't posted a pix in so long I forget how. :-)
                        There isn't an attach so I'd have to put it on Photobucket and right now my
                        darn browser is so screwed up (tried to up date it) I don't want to make it worse.
                        ...lew...

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                        • #13
                          Lew, email the picture or a link and I'll post it for you.

                          Are you saying you cut a 90° notch that's rotated 45°, so you end up with V-ways?
                          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                          • #14
                            If you want to make it stronger, forget the pins and use shoulder screws instead at all four positions on each piece.

                            Personally, I don't like the dovetail design.







                            Shop built. All adjustments are independent of each other and it repeats to 0.001". I can easily change tools with one hand. Rock solid!!! The holder doesn't hang on one side of the post like the dovetail designs, it surrounds it and effectively becomes one solid piece of steel.

                            And no dovetails.
                            Last edited by Paul Alciatore; 08-15-2009, 02:00 PM.
                            Paul A.

                            Make it fit.
                            You can't win and there is a penalty for trying!

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                            • #15
                              Very nice work. It should be very gratifying to produce something like that.
                              Byron Boucher
                              Burnet, TX

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