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Amount Of Force Needed To Shear 12Ga. Stainless Sheet

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  • Amount Of Force Needed To Shear 12Ga. Stainless Sheet

    I have a few strips of stainless sheet, 12ga. .109. I had the strips sheared at 3 1/2" in width. I should have specified 3 1/4"
    Anyway, I've set some of the pieces up on my mill after I cut them to length and used a slitting saw to trim them, but that's pretty time consuming.

    So If I were to make a shear, a short one that could cut perhaps 6" in length and set up an edge guide and a way to hold the piece down, how much force is needed to shear this stuff?

    I would have to come up with some sort of leverage multiplier set up like bolt cutters have. Something on that order.
    I guess it depends on the angle of the blade also. When a shear cuts it point contact moving along the piece.

    JL................


  • #2
    I'm thinking something along the lines of this design. Di Acro makes a short 6" shear but they are only rated at 16 ga. mild steel.



    JL............
    Last edited by JoeLee; 09-11-2019, 09:02 PM.

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    • #3
      My chart says 4 tons per linear inch for 12 ga stainless vs 2.75 tons for mild steel if that helps any.Here's an online chart,but it doesn't list 12 ga-

      http://freetechnicalcharts.com/Shear...e_Required.php

      As far as a bought item goes,one of these would most likely do it,compound leverage,does 2" angle and decent sized round bar too.

      https://www.ebay.com/itm/Bar-Section....c100010.m2109
      I just need one more tool,just one!

      Comment


      • #4
        Do you need to make many of these? An abrasive (thin blade) or even a bandsaw will make short work, unless you are in production mode. JR
        My old yahoo group. Bridgeport Mill Group

        https://groups.yahoo.com/neo/groups/...port_mill/info

        Comment


        • #5
          Originally posted by wierdscience View Post
          My chart says 4 tons per linear inch for 12 ga stainless vs 2.75 tons for mild steel if that helps any.Here's an online chart,but it doesn't list 12 ga-

          http://freetechnicalcharts.com/Shear...e_Required.php

          As far as a bought item goes,one of these would most likely do it,compound leverage,does 2" angle and decent sized round bar too.

          https://www.ebay.com/itm/Bar-Section....c100010.m2109
          Thanks for the info. Now I have to come up with a way to get that much force to a hand operated shear blade.

          Those bar cutters don't have a blade long enough for what I want to do. They are designed for chopping rod, angle and stuff like that. There is no table either. Basically a big pair of bench mounted bolt cutters.

          This leads me to another idea. If I could make a shear less the handle and leverage multiplying linkage I could use my 15 ton press to push the blade down through the material.
          I'll have to sketch up some ideas.

          JL...........
          Last edited by JoeLee; 09-11-2019, 11:10 PM.

          Comment


          • #6
            Originally posted by JRouche View Post
            Do you need to make many of these? An abrasive (thin blade) or even a bandsaw will make short work, unless you are in production mode. JR
            I don't need to make many of these right now, maybe about 6 of them for various size U-bolt saddles. The width of 3 1/4" is the same for all as shown in my picture.

            I do have a bandsaw but it doesn't make a good finish cut. The shear makes a nice smooth rolled off edge on the cut. I would like a shear fixture for future use and fast accurate cuts with good repeatability.

            Layout is very important when I hole saw and dill the holes. Off a few thou and when the clamp is formed the circles won't line up perfectly and the saddle won't sit square on the tube.

            Just trying to think ahead here.

            JL................

            Comment


            • #7
              For an approximation of force, multiply shear strength of the material by the shear area.

              Or just use the charts.

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              • #8
                Originally posted by JoeLee View Post
                This leads me to another idea. If I could make a shear less the handle and leverage multiplying linkage I could use my 15 ton press to push the blade down through the material.
                I'll have to sketch up some ideas.

                JL...........
                That is a good option. I tried it on my press and didnt make a good shear (HF 9" blades). The clamping while shearing is what screwed me up. This after I already made a lower and upper fixture for the press

                Stuff happens and it can be a long road. I did rig up a back up clamp so it would cut instead of tear. This was when I was young (20 ago) and liked to hot weld

                Bones are too hurting now.

                Sounds like a fun project. Need anymore 4140 PH rods JR
                My old yahoo group. Bridgeport Mill Group

                https://groups.yahoo.com/neo/groups/...port_mill/info

                Comment


                • #9
                  Originally posted by JoeLee View Post
                  Thanks for the info. Now I have to come up with a way to get that much force to a hand operated shear blade.

                  Those bar cutters don't have a blade long enough for what I want to do. They are designed for chopping rod, angle and stuff like that. There is no table either. Basically a big pair of bench mounted bolt cutters.
                  The shear on those is a bypass type just like the one in your first post,only heavier.Being a bypass shear,it can shear an infinite length,just not in one chomp.It lists the "flat strip" capacity at 3.54x .39 inches,but the blade length listed is 7".

                  Originally posted by JoeLee
                  This leads me to another idea. If I could make a shear less the handle and leverage multiplying linkage I could use my 15 ton press to push the blade down through the material.
                  I'll have to sketch up some ideas.

                  JL...........
                  It's gonna have to be pretty beefy.I have a Pexto/Wilcox 12" bypass shear that will cut 3/16" mild steel,it also weighs 600lbs.
                  I just need one more tool,just one!

                  Comment


                  • #10
                    If you've not seen it already, there is a "This Old Tony" video about building a shear similar to that, it may provide some design ideas or inspiration. I have a small Beverly Jr. throatless shear of that design. It won't do 12 gauge, I think 16 is about the limit, but it is a super handy thing to have on hand. I got it as a sort of extra in a lot of stuff I bought and found that I use it quite often for something or other.

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                    • #11
                      Be careful shearing stainless. It gives a nice rounded edge on one side, but the other side can be super sharp. When I worked on contracts involving stainless roofing sheets, the roofers hated the stuff because of those razor edges. That and the glare in a summer sun.
                      Rebar fixers don't like stainless tie wire either, always snagging themselves on sharp projecting wire ends where they've been snipped to length.
                      'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

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                      • #12
                        There are a few you tube videos on these like the one I posted a pic of. Somewhere they list the cutting capacity at 3/16" mild steel. I would think it should cut 12ga. ss.

                        What I'm curious about is the blade design...... they all have a curved upper blade as opposed to a drop shear which has a straight blade set at an angle to give point contact along the shearing length. Why are the short one curved?? I take it the curved blade design is so point contact is maintained throughout the movement range of the blade. If it were a straight blade teh contact angle would change as it closes. Am I right??

                        I'm almost tempted to buy one of those and add a table and stop fence for repeated accuracy.

                        I would like to see what both sides of a piece of sheared material looks like when done on one of these.

                        JL...............

                        Comment


                        • #13
                          Originally posted by JoeLee View Post
                          There are a few you tube videos on these like the one I posted a pic of. Somewhere they list the cutting capacity at 3/16" mild steel. I would think it should cut 12ga. ss.

                          What I'm curious about is the blade design...... they all have a curved upper blade as opposed to a drop shear which has a straight blade set at an angle to give point contact along the shearing length. Why are the short one curved?? I take it the curved blade design is so point contact is maintained throughout the movement range of the blade. If it were a straight blade teh contact angle would change as it closes. Am I right??
                          Yes,the angle would change and the tonnage required would increase as well.

                          Originally posted by JoeLee
                          I'm almost tempted to buy one of those and add a table and stop fence for repeated accuracy.

                          I would like to see what both sides of a piece of sheared material looks like when done on one of these.

                          JL...............
                          Simple,the saved piece is usually straight with a slight burr on the bottom.The waste piece is curved and twisted and generally scrap.The 3/16" mild steel claim is optimistic at best. I've used probably a dozen different brands of that same shear in 4" thru 8" blade models and the frames get pretty springy on anything above 14 ga mild steel even on the models that include a hold down.It's the exact same problem encountered when trying to cut something too thick with a pair of scissors,the blades simply spring open away from each other(clearance opens up).

                          That's why I posted the link to that bigger cutter,it's has a much heavier frame,the tonnage requirement isn't linear.

                          Here's a video on making a bypass shear,this could be scaled up-

                          https://www.youtube.com/watch?v=LzpV6T9Yltc

                          And then there are the guillotine shears made to work in hydraulic ironworkers,this one does 1/4x6" flatbar

                          http://www.edwardsironworkers.com/p-....l6UHdphX.dpbs
                          I just need one more tool,just one!

                          Comment


                          • #14
                            I watched that video last night.

                            The last time I had some of this stuff sheared they must have cut both sides off the table rather than having the piece end up being the drop.
                            There is a difference in the edges.

                            The piece shown in my first post has the rounded edges on both sides. That's the way I would like all of it.
                            The last piece I had sheared had one nice rounded edge and the other edge was flat and sharp, that was the drop.

                            I guess unless I specify how to shear it that's what I get. This is why I would like to make my own shear for these.

                            JL.............

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                            • #15
                              I think the curved blade shear allows it to cut a radius. . curved cuts.

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