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I need a Radii Maker for 2" radius.

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  • I need a Radii Maker for 2" radius.

    I have a 3S/3D radii cutter for my lathe. It will cut a 2" inside (concave) radius but it will only cut a 1 11/16" outside radius. I need to cut a 2" matching radius.

    Next size larger radius cutter is 4D but it will not fit my lathe plus it costs $1200.00.

    I need some PLANS to build a radii cutter that will do 2 inches. I am hoping someone has a very simple idea how to cut a 2" radius or plans to build a simple cutter.

  • #2
    How is the top slide mounted?
    Free software for calculating bolt circles and similar: Click Here

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    • #3
      What IS the lathe??

      Regards Ian.
      You might not like what I say,but that doesn't mean I'm wrong.

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      • #4
        could a modified 2" trailer ball be used in your project?
        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
        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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        • #5
          Is this the radii cutter you have? It states that it will do up to 3" balls.

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          • #6
            A 4 inch ball. 2 inch radius is quite large. What size lathe do you have? Need this info to come up with possible ways of doing the job.

            Bob

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            • #7
              That looks like the radius cutter I have in the link.

              I have a Churchhill 12" x 36" Lathe.

              What I am making is a punch press forming die. The bottom die is 2" diameter with a 2" concave radius. Place a .062" thick x 2" diameter metal plate on the die surface. The top die comes down and forms the flat metal plate into a dish shape. The top die has to be 2" radius minus the metal thickness. Radius on the top die should be 1.938".

              Here is a pic of a radii cutter exactly like mine. http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT
              Last edited by ; 10-09-2009, 12:59 PM.

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              • #8
                lol...yeah, radius and diameter are not the same thing...it's gonna be one of those days

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                • #9
                  Whoa, if you're trying to press a hemisphere, think about using a RING die first, coining takes carefull adjustment and can lead to a broken press crank.

                  Regards Ian.
                  You might not like what I say,but that doesn't mean I'm wrong.

                  Comment


                  • #10
                    Originally posted by Circlip
                    Whoa, if you're trying to press a hemisphere, think about using a RING die first, coining takes carefull adjustment and can lead to a broken press crank.

                    Regards Ian.
                    I am using a hydraulic press. It only takes about 2 tons to bend this tiny little metal plate into a dish shape.

                    The metal circles are exactly round 2.000" diameter. They lay on top of the 2" die and get pressed. The metal disc is greased on both sides. It press like butter, nothing hard about this. This is not a progressive die just a 1 station manual die.

                    Here is a pic of the top and bottom die and a part I made by pressing it in the milling machine vise. The center of the part has a flat place 1/2" wide. It is also suppose to have a 1/4" hole for bolting it to something else. I ruff cut the top die by turning it 500 rpms on the lathe and using a 4000 rpm disc sander to shape the part using a radius guage. The part is pretty close at this point but not right on. I can see my top radius is not correct because it did not press the flat place in the metal plate.
                    Last edited by ; 10-09-2009, 03:36 PM.

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                    • #11
                      Hmm, offhand it seems likely that it might be possible to make a new, deeper yoke for your Holdridge rig. If you mounted the main casting at an angle or even ninety degrees from the normal orientation, your new deep yoke wouldn't have to clear the casting to rotate through the necessary arc.
                      Cheers,

                      Frank Ford
                      HomeShopTech

                      Comment


                      • #12
                        Originally posted by gary350
                        I have a 3S/3D radii cutter for my lathe. It will cut a 2" inside (concave) radius but it will only cut a 1 11/16" outside radius. I need to cut a 2" matching radius.

                        Next size larger radius cutter is 4D but it will not fit my lathe plus it costs $1200.00.

                        I need some PLANS to build a radii cutter that will do 2 inches. I am hoping someone has a very simple idea how to cut a 2" radius or plans to build a simple cutter.
                        Where are you located?? I have the 4d and would letcha use it if you were local.. I think it will work on yer 12" lathe.. JR

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                        • #13
                          plans . . .

                          I really don't see where you need plans for a yoke type cutter. I do have an amusing paper I wrote about making an Over-Engineered Spherical Turning Tool which turned out to be an incorrect fit for the balls I needed. It includes plans. I think it is still at:

                          <http://www.metalwebnews.com/howto/turning-tool/spherical_turning_tool.pdf>

                          I know it is still at the yahoo Quorn TC&G files section.

                          I'll try to get a picture in here. Humm, OTOH, I don't see an upload pic section. :-(

                          - Reed

                          Originally posted by gary350
                          I am using a hydraulic press. It only takes about 2 tons to bend this tiny little metal plate into a dish shape.

                          The metal circles are exactly round 2.000" diameter. They lay on top of the 2" die and get pressed. The metal disc is greased on both sides. It press like butter, nothing hard about this. This is not a progressive die just a 1 station manual die.

                          Here is a pic of the top and bottom die and a part I made by pressing it in the milling machine vise. The center of the part has a flat place 1/2" wide. It is also suppose to have a 1/4" hole for bolting it to something else. I ruff cut the top die by turning it 500 rpms on the lathe and using a 4000 rpm disc sander to shape the part using a radius guage. The part is pretty close at this point but not right on. I can see my top radius is not correct because it did not press the flat place in the metal plate.
                          http://i43.photobucket.com/albums/e3...0/000_0005.jpg

                          Comment


                          • #14
                            Here's my large radius solution, don't know if it would be rigid enough for a large steel ball, I've done mostly PE and modeling foam:

                            Location: Jersey City NJ USA

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                            • #15
                              *** Note: Just general comments, not directed toward anyone. :-)

                              I have a weldment I cobbled together for turning up some roller tubing dies. It was ugly, but quickly created and efficient. :-) I needed 5/16" and 7/16" radius for 5/8" and 3/4" tubing. Not much stress as it is the cut depth/feed and not the radius of piece.

                              I highly suspect Gellfex's cutter would would be quite adequate for his job given the picture (rather stout frame). Funny thing I quickly noticed back then was using a lever to feed the cutter was perfectly good instead of any geared arrangement. That worm gear I used was a waste of time.

                              - Reed

                              Originally posted by gellfex
                              Here's my large radius solution, don't know if it would be rigid enough for a large steel ball, I've done mostly PE and modeling foam:

                              http://bbs.homeshopmachinist.net/sho...s+tool+gellfex
                              Last edited by Reed; 10-10-2009, 11:02 AM.

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