OT: (WW) Simplest jig to flatten angle iron end for truss webbing
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  1. #1
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    Default OT: (WW) Simplest jig to flatten angle iron end for truss webbing

    The question may be more suited to Welding Web, but since it's still down, and this is actually a tool/jig making question, please forgive me.

    I'm getting ready to make a first sample K joist (title is incorrect - joist, not truss), for more info see this other thread. Aside from making stands to keep the angle irons all parallel and in-plane, my other piece of prep work is to make an easy way to collapse the ends of the angle iron pieces that will form the webbing. The angle is 1-1/4" with 5/32" wall, so it's not especially difficult to form - but I want an easily repeatable way to make sure it ends up 1" wide (outside to outside) because it having a uniform thickness between the main angle runs will contribute to the uniformity of the width of the overall joist.

    I can get a decent bend on it just using my Columbian vise with a solid round held in the gap. However, first, it feels like I'm stressing the vise screw pretty good, and second, if you look at the pics of the test fitup, it didn't give me a very good flat to weld against on the back side of the bend. The bend is such that it's going to be tough getting a good angle to weld the back side (the contacting side nearest the angle's outside corner).

    img_20200210_161015.jpg

    image7463159345687800973.jpg image9003132627339635625.jpg img_20200210_161337.jpg img_20200210_161331.jpg

    So, how is this done commercially? I have a 25t shop press, which seems like the right tool for this job. I assume that someone sells an attachment for a shop press or iron worker to do exactly what I'm trying to do, but I can't figure out what to search for in order to see how they're doing it.

    I think that because of the deflection, my two pressing surfaces (the jaws, in the vise example) actually need to be not parallel to each other, but collapsed a bit inward on the angle's open side (top side in the vise pic) - because it needs to overbend that part in order to end up with the two angle legs parallel because they're going to spring back some.

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    Beeg fooking hammer....

    Seriously, have you tried a flat bar as the "squash flat to this" in the center ?
    Seeing how it's a simple press, I would machine a small "v" notch both on the punch,
    as well as the bottom flat. To engage the end of each leg, and hold them there.

    This will keep them directly above each other, and in a vertical plane coming down.

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    Quote Originally Posted by digger doug View Post
    Beeg fooking hammer....

    Seriously, have you tried a flat bar as the "squash flat to this" in the center ?
    Seeing how it's a simple press, I would machine a small "v" notch both on the punch,
    as well as the bottom flat. To engage the end of each leg, and hold them there.

    This will keep them directly above each other, and in a vertical plane coming down.
    Yes, a flat "anvil" makes a lot more sense. Good thinking.

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    Use round bar for the diagonal shear webbing. It will be a whole lot easier. Who is engineering this? Here in the US truss manufactures have licensed engineers to certify the design. Don’t take chances. There is a whole lot more to truss design than cutting and welding.

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    Quote Originally Posted by mach2 View Post
    Use round bar for the diagonal shear webbing. It will be a whole lot easier. Who is engineering this? Here in the US truss manufactures have licensed engineers to certify the design. Don’t take chances. There is a whole lot more to truss design than cutting and welding.
    Uhm....You need to read this thread, already been hashed and re-hashed:
    OT: Anyone ever run across a simple table of steel roof truss loads?

    1. Round bar for the web is for smaller/lighter bar joist, consult the table.
    2. flattened angle for the webs are bog standard, next time your in Lowes/Walmart/Home depot, look up ^

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    Notice this thread is from the same original poster.

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    Quote Originally Posted by digger doug View Post
    Uhm....You need to read this thread, already been hashed and re-hashed:
    OT: Anyone ever run across a simple table of steel roof truss loads?

    1. Round bar for the web is for smaller/lighter bar joist, consult the table.
    2. flattened angle for the webs are bog standard, next time your in Lowes/Walmart/Home depot, look up ^
    OP said joist and that implies shorter spans. Joists and trusses can be made with any steel sections you want. Thats what the engineers are for. Rod is easier to bend into truss webbing than angle. If angle was used I would think coping the ends would work better than smashing them.

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    Quote Originally Posted by mach2 View Post
    OP said joist and that implies shorter spans. Joists and trusses can be made with any steel sections you want. Thats what the engineers are for. Rod is easier to bend into truss webbing than angle. If angle was used I would think coping the ends would work better than smashing them.
    Please !
    Go and re-read the linked.

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    A fly press and simple tooling?

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    Quote Originally Posted by digger doug View Post
    Uhm....You need to read this thread, already been hashed and re-hashed:
    OT: Anyone ever run across a simple table of steel roof truss loads?

    1. Round bar for the web is for smaller/lighter bar joist, consult the table.
    2. flattened angle for the webs are bog standard, next time your in Lowes/Walmart/Home depot, look up ^
    Round would be simpler to fab, and there is a spec for this size joist using round, but it was waaay bigger than I can get here (may have been 7/8" or 15/16"), so angle is my only option for a joist this size. It won't be bad, once we get a good flattening process set up.

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    probably the easiest with what you have available would be a jig with stops at the width/hight you want plus deflection and a top plate then use your press, of course it may not bend completely evenly that's the only way i can think of to get somewhat consistent results. using a vise makes my arm hurt thinking bout it

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    Quote Originally Posted by JasonPAtkins View Post
    Round would be simpler to fab, and there is a spec for this size joist using round, but it was waaay bigger than I can get here (may have been 7/8" or 15/16"), so angle is my only option for a joist this size. It won't be bad, once we get a good flattening process set up.
    Jason. I know that, and you know that (we hashed out a plan in the other thread), I was trying to explain it to the twinky, the one that refused to follow the linky to the other thread, and read it.

    BTW was looking thru those linked documents from egn-tips.com again
    The one marked "DeLong joists" shows the larger ones, made only from angle, and note the orientation
    of the web members, not like a normal bar joist.

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    Quote Originally Posted by digger doug View Post
    Jason. I know that, and you know that (we hashed out a plan in the other thread), I was trying to explain it to the twinky, the one that refused to follow the linky to the other thread, and read it.

    BTW was looking thru those linked documents from egn-tips.com again
    The one marked "DeLong joists" shows the larger ones, made only from angle, and note the orientation
    of the web members, not like a normal bar joist.
    Thanks, Doug - sorry, I lost track of who was up to date and who hadn't read the old thread, lol.

    When that Delong Truss doc was suggested, I went and searched for it on the eng-tips site but couldn't find it using either of that site's search tools. Would you mind giving me a link directly to it? I'm now thinking I need an 18" truss (sounded like that chart was 18" and up) and hadn't found any specific spec on the web angle size and thickness, which sounds like you're saying it has, and also hadn't found clarification on the web orientation, and which ones go smashed between the long angles and which get welded to the outside face. That doc sounds helpful.

    Thanks!

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    Quote Originally Posted by JasonPAtkins View Post
    Thanks, Doug - sorry, I lost track of who was up to date and who hadn't read the old thread, lol.

    When that Delong Truss doc was suggested, I went and searched for it on the eng-tips site but couldn't find it using either of that site's search tools. Would you mind giving me a link directly to it? I'm now thinking I need an 18" truss (sounded like that chart was 18" and up) and hadn't found any specific spec on the web angle size and thickness, which sounds like you're saying it has, and also hadn't found clarification on the web orientation, and which ones go smashed between the long angles and which get welded to the outside face. That doc sounds helpful.

    Thanks!
    Found it !
    http://files.engineering.com/downloa...es_Catalog.pdf


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