Section bender dies

  1. Thrashsmith

    Thrashsmith Member

    Messages:
    613
    England, Kent
    I bought a powered ring/section roller the other day, not a commercially made set, they're a very well made home made set. I think I'm the 3rd owner, including whoever made them.
    They've only got flat rollers on currently but with a bit of jiggery pokery I think some dies could be slipped on that will prevent box section/circular hollow from deforming.

    Question is: if I was rolling 40mm SHS for example, how much of the vertical face needs to be covered to prevent it pooching out? I've attached a crappy sketch to help illustrate what I mean.

    I'm not looking roll 40mm SHS specifically, it's more of a generalized question. How much of the profile needs covering to prevent drastic distortion? One third? Half?
    Cheers
    20200830_174630.jpg
     
  2. Hitch

    Hitch Moderator Staff Member

    Messages:
    12,462
    Somerset
    The outer formers do part and the inner former does part, from memory, the rollers on the one where i used to work were about 30mm deep...but that was intended to do various sections.

    Looks like it setup for about 50x50 box in the pic...
     
    • ercolrolls.JPG
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  3. Thrashsmith

    Thrashsmith Member

    Messages:
    613
    England, Kent
    Thanks, though t.b.h I'm struggling to make out which bit is which :doh: Where does the 30mm dimension you mention relate to?
     
  4. Hitch

    Hitch Moderator Staff Member

    Messages:
    12,462
    Somerset
    Is that what you want to know?
     
    • ercolrolls2.jpg
  5. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Messages:
    16,028
    Location:
    East Yorkshire
    I’ve machined dies for 5/8" and 19mm sq thin wall box section. Had about 60% depth. Go steady and it doesnt deform unless you want sub 6/900mm rads
     
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  6. Thrashsmith

    Thrashsmith Member

    Messages:
    613
    England, Kent
    Really sorry but I'm a bit lost, I appreciate your effort though!

    I've attached a pic of the rollers + a bad sketch over the top. On that sketch picture, if I was rolling 40mm box, how deep would you imagine those "grooves" would need to be to prevent the 40mm box from pooching out? VideoCapture_20200830-190607.jpg 20200830_190821.jpg
     
  7. Hitch

    Hitch Moderator Staff Member

    Messages:
    12,462
    Somerset
    Hows this... picture turned the same orientation of your machine...
     
    • ercolrolls2t.jpg
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  8. Spark plug

    Spark plug Member

    Messages:
    3,779
    Location:
    Durham, England
    You can also make your dies like this, sa ring making a specific die for every size of material:

    0E7ED223-9D63-46B5-9747-65C28D7B89D3.jpeg
     
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  9. Thrashsmith

    Thrashsmith Member

    Messages:
    613
    England, Kent
    Gotcha! Cheers :drunk:
     
  10. mike os

    mike os just a little insane.....

    Messages:
    6,971
    Location:
    North Wales
    guessing the smaller the gap the better without being tight?
     
  11. Thrashsmith

    Thrashsmith Member

    Messages:
    613
    England, Kent
    So presumably with a system like this you're meant to arrange the inner pieces so that they arrange to being the same diameter as the section you're rolling? Eg 50mm box?

    This is a pic of the 3 rollers on mine in various stages of assembly. The top one is fully assembled, the right one has the end plate unscrewed & the left one has one of the 30mm diameter inner pieces removed (as well as the out bits). The outer bit with the lip is separate to the 30mm inner piece. 20200830_133406.jpg
     
  12. bletchmonster

    bletchmonster Member

    Messages:
    488
    Location:
    Cheshire. England.
    With standard 40/50 x 3mm box section my rollers use the big washer and different sized spacers as previously mentioned.
    As the box is rolled it gets fatter and the nut on the shaft has to be slackened so the washers are only just kissing the box.
    Trying to keep the box in exactly its original profile makes it gall up and jam to the point that no amount of power will keep it rolling.
    Circular section rolls in fixed dies no problem.
     
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  13. bletchmonster

    bletchmonster Member

    Messages:
    488
    Location:
    Cheshire. England.
    IMG_20200831_101719.jpg
     
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  14. KemppiFrog Member

    Messages:
    3,377
    Location:
    Aquitaine
    My rollers are 60mm diameter and the end flanges 11mm deep. That is for 50 RHS, but I think the 40 ones are the same. I had them machined, but can't remember why I chose that size. They do work OK though.
     
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  15. Thrashsmith

    Thrashsmith Member

    Messages:
    613
    England, Kent
    bletchmonster likes this.
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