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  • Bending Rolls

    I thought some of you guys might be interested in a little project I just finished. It is a set of bending rolls which I will be using to form some guards and other bits and pieces for a much longer term project - classic make the tools to make the tools situation ...

    The rolls are from a Hemmingway kit, which in turn is based on a classic George Thomas design. I made a few minor modifications but it is essentially the original design. The idea is to use a rear mounted deflecting roll rather than the more typical pyramid arrangement. This is supposed to have some advantages in that the radius being rolled can continue right up to the end of the stock, rather than having flats at each end. This does work as intended, although it is necessary to reverse the stock on each pass.

    The overall layout:



    the rolls are intended to be held in a vice as shown. The gears provides a positive feed to the two front rolls, which pinch the work under the control of the screws at the top.



    Since the front rolls need to adjust to accommodate different thicknesses of stock, the gear arrangement has to allow for this.

    The latches on top open so that if a complete ring is rolled, the stock can be removed with the roller. The bronze bearings have inset hardened steel pads so that the bronze doesn't get damaged by the ends of the screws. There is a similar arrangement for the bearings holding the rear deflecting roll, which has a much longer range of adjustment.


    View from the back:

    Bill

  • #2
    That is a great tool! Did you make CAD drawings for the parts? I have been wanting to build a leather splitter that is crank operated. What you have there would work almost perfectly with just a small bit of modification.

    Did you make the gears yourself?
    Location: The Black Forest in Germany

    How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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    • #3
      The roller that is adjusted to make the actual bend could be replaced by a blade and a containment apparatus. The driven rollers would actually pull the leather not push the leather.

      .......I feel a project coming on!
      Location: The Black Forest in Germany

      How to become a millionaire: Start out with 10 million and take up machining as a hobby!

      Comment


      • #4
        The drawings with the kit are copyright so I can't give you those, but the original George Thomas article is here:
        http://www.metalwebnews.com/howto/ro...ndingRolls.pdf
        That has the original drawings in it. There are only minor differences between that one and the version that I made. I think it is worth the effort to add the captive tommy bars as I have done, it only takes a few minutes to make them.

        I don't know what leather splitters do- can you explain?
        Bill

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        • #5
          Originally posted by Black Forest View Post
          Did you make the gears yourself?
          No - the gears came with the kit. They are just standard off the shelf parts - all you need is four the same size, preferably two with keyways already in. If you can't get them with keyways you would need to put them in yourself. I made the keyway in the handle with just a couple of files - it takes a while to do it that way, but cheaper than buying broaches.
          Bill

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          • #6
            Originally posted by willmac View Post
            There are only minor differences between that one and the version that I made. I think it is worth the effort to add the captive tommy bars as I have done, it only takes a few minutes to make them.
            What is a tommy bar?

            John
            My Web Site

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            • #7
              I think I am looking at this correctly...
              There is a similar arrangement for the bearings holding the rear deflecting roll, which has a much longer range of adjustment.
              , is that the "slot" with the bronze widget partially hidden by the crank are in photo # 2 ?

              Comment


              • #8
                Originally posted by willmac View Post
                The drawings with the kit are copyright so I can't give you those, but the original George Thomas article is here:
                http://www.metalwebnews.com/howto/ro...ndingRolls.pdf
                That has the original drawings in it. There are only minor differences between that one and the version that I made. I think it is worth the effort to add the captive tommy bars as I have done, it only takes a few minutes to make them.

                I don't know what leather splitters do- can you explain?
                Leather splitters split leather! The leather is pulled over a long blade and split to a desired thickness. Leather as it comes from the cow is not a uniform thickness so for a lot of work it must be split to a uniform thickness. On a wide piece it is quite difficult to hand pull the leather through the blade. Typically on a leather splitter with a crank the lower driven roller is serrated to give traction. The flesh side of the leather goes against the serrations so as not to mark the smooth side. A good old cranking leather splitter is a Landis Model 30 for shoe sole splitting but they are hard to come by nowadays.
                Location: The Black Forest in Germany

                How to become a millionaire: Start out with 10 million and take up machining as a hobby!

                Comment


                • #9
                  Willmac,

                  Nice job on the roller. I made a small 19" press brake recently and a roller like that would complement it nicely.

                  It is now on my to do list.

                  Brian

                  PS. That would also be a great candidate for the shop made tools thread.
                  OPEN EYES, OPEN EARS, OPEN MIND

                  THINK HARDER

                  BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

                  MY NAME IS BRIAN AND I AM A TOOLOHOLIC

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                  • #10
                    Originally posted by BigJohnT View Post
                    What is a tommy bar?
                    John
                    The little bar with two ends on it that adjusts the screw. It gives a bit of extra leverage compared to knurling the top of the screw. I don't know where 'tommy' comes from; its UK terminology and maybe a bit old-fashioned.
                    Bill

                    Comment


                    • #11
                      Originally posted by RussZHC View Post
                      I think I am looking at this correctly..., is that the "slot" with the bronze widget partially hidden by the crank are in photo # 2 ?
                      Yes that is correct. The bronze bearing is similar to the one for the top roller, just a bit smaller. The screws are 'timed' so that when the deflecting roller is in its fully up position, the tommy bars are aligned. This means that you can get the deflecting roll parallel by counting turns on each side and making sure the tommy bars line up. The top adjusters are done the same way.
                      Bill

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                      • #12
                        Where would one find beefy gears like those off the shelf?

                        Comment


                        • #13
                          Very nice set of rolls Willmac!
                          I just need one more tool,just one!

                          Comment


                          • #14
                            Rolled pinion stock,just bore the shaft hole and part off the width you want.

                            http://www.grobinc.com/coldrolled/std_spur_gears.htm

                            Boston gear,McMaster and several others also carry it.
                            I just need one more tool,just one!

                            Comment


                            • #15
                              Originally posted by dp View Post
                              Where would one find beefy gears like those off the shelf?
                              Here:http://www.maedler.de/Product/1643/1...1066/1070.aspx
                              Location: The Black Forest in Germany

                              How to become a millionaire: Start out with 10 million and take up machining as a hobby!

                              Comment

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