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  • Trepanning, sort of....

    Doing a little prototyping for work today, and needed to create a 70mm bore in a 1" thick piece of alloy.
    Rather than just drill and bore, creating loads of swarf I thought Id trepan out the center slug. only problem was I dont have a trepanning tool...
    So root about and find a Hole saw on a plain arbour. Mount in a boring tool holder, set square and on center, then use tailstock to push the whole lot so the twisting forces on the toolpost which you'd get if you used the powerfeed are not present.
    Handily the female center for my changeable center set is just the right size.





    The hole provided a very good place to pour coolent without it going everywhere.



    Done:




    Dave
    Just south of Sudspumpwater UK

  • #2
    And a more finished shot of the prototype, just before lunch...



    Dave
    Just south of Sudspumpwater UK

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    • #3
      Whatever you do, don't hold a holesaw for a job like that in a keyless tailstock chuck.

      Don't ask me how I know this.......

      Tim

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      • #4
        trouble getting it out again?

        Comment


        • #5
          Nice job.. I hate the unflated smaller arbor for my hole saws...
          Random tip: grind flats into the arbor so a wrench will fit it for removal (from the hole saw)
          Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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          • #6
            Thou needs one of these.



            The universal R8 hole saw [TM]
            Two sizes 1/2" x 20 thread and 5/8" x 18 thread, with or without pilot drill.

            .
            .

            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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            • #7
              Small Planes,

              That's pretty cool. I'll bet I'm using that little trick very soon. It looks like you are working in aluminum and I wonder how long the hole saw would last in something like mild steel or harder. I have using Champion RotoBrute hole saws for a while with my mag drill. They are carbide toothed hole saws that cut up to 2" thick steel. I was in Lowes the other day and noticed some similar hole saws by Ideal in the electrical section. They may have been a little cheaper.

              All the best,

              Tim

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              • #8
                I love the coolant feed there. Massive quantities of coolant is probably something holesaws aren't that familiar with.

                Comment


                • #9
                  Nice setup.

                  For an old semi-regular job I had to cut 4 and 3/8 steel disks out of 1.5 inch plate, materials were supplied and were 5x2 stock.
                  Best method I figured out was to set the material on a scrap of plywood on the drill press, set to to the lowest speed, set up the flood, and hook a bungie cord to the down feed. Turn it on and go do something else.

                  That's the job that -really- taught me that slower is better with a large hole saw. I 'knew' it before that, but really learned it on that job.

                  Ken.

                  Comment


                  • #10
                    Originally posted by John Stevenson
                    Thou needs one of these.



                    The universal R8 hole saw [TM]
                    Two sizes 1/2" x 20 thread and 5/8" x 18 thread, with or without pilot drill.

                    .
                    Nope, I dont have any liquorice R8 machines in my workshop.
                    Now if they were INT40 that would be a different matter

                    The Arbour was actually made to use in ER collets on the mill, but boring the hole to exact size is so much easier on the lathe than with the boring head in the mill.

                    TMC31,
                    These are essentially hacksaws in a circle. Ive done quite a few holes in 10mm mild steel plate with this one and its holding up fine. They are not woodworking holesaws.

                    Dave
                    Just south of Sudspumpwater UK

                    Comment


                    • #11
                      Originally posted by CountZero
                      trouble getting it out again?
                      Yes, the combination of the saw vibration and the hex shank on a standard holesaw arbor works to tighten the chuck more.......and more.......and more..... to the point where it won't undo. I lost a perfectly good Rohm chuck doing that

                      Tim

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                      • #12
                        Looks as if the hole saw was set off center (or centre?) a bit horizontally. Was that done intentionally to allow clearance and chip escape?
                        Jim

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                        • #13
                          Originally posted by Timleech
                          Yes, the combination of the saw vibration and the hex shank on a standard holesaw arbor works to tighten the chuck more.......and more.......and more..... to the point where it won't undo. I lost a perfectly good Rohm chuck doing that

                          Tim

                          I almost had that problem yesterday with a 1.5" drill and an Albrecht chuck in the lathe tailstock. Went to loosen it and it wanted to take my skin. I did not want to marr it up with water-pumps so I used a belt wrench and a couple of jars and it loosened up for me.

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                          • #14
                            Thanks for the post. I've avoided boring small holes larger every chance I get! I think I'll gear up to do it as Sir John suggested. I just don't have the patience to do a lot of boring just to see if something is going to work.
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                            Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

                            It is true, there is nothing free about freedom, don't be so quick to give it away.

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                            • #15
                              Annular Cutters

                              I've used these a lot. They hands down beat using a hole saw. They are expensive, but well worth it for the time they save.

                              http://www.hougen.com/cutters/cutters_index.html
                              Sometimes the professional is hidebound by tradition while the skilled amateur, not knowing it can't be done blazes a new trail. -JCHannum

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