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How much of 1/4" plate can I bend with a 3/16" apron brake.

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  • How much of 1/4" plate can I bend with a 3/16" apron brake.

    I just bought a power apron brake that is rated for 10' x 3/16" mild steel.

    With this being said, can I bend a lessor amount of 1/4" plate and if so how much.

    This is a Dreiss Krump.

    To watch it bend 3/16" at 10' seems effortless.

  • #2
    Check the offset where the apron comes up in front of the fingers or whatever it bends against. If it is too tight it may damage your brake to bend thicker material. Think about what would bind if your were to put a piece of 3/4" plate in there. Thinner plate will have the same effect to a lesser degree. That is to say that the thickness you can bend is limited by the position of the center of the hinges in relation to front of the hold down clamp.---Meltedmetal


    • #3
      Thanks Melted Metal, I do realize that I need to be able to push the head back in order to make room for the thickness of the material, along with additional room for the radius, My thoughts are that the farther I push it back the less tonnage will be required.


      • #4
        Well, it's 25% thicker so maybe 25% less length will be similar load. Say 7 1/2 ft.
        Old Miller Swinger 180 Buzzbox
        Miller Diversion 165
        1945 Craftsman Atlas Lathe
        Smithy Lathe/Mill


        • #5
          With so few replies I'm thinking that the guys that used to run this kind of brake are all dead, There are very few big ones like this on Ebay, even fewer on Craigslist and have only ever seen one in a shop in my 28 years.

          I have seen small ones in the 12 ga. range on down but only 1 big one in my 28 years.

          While I have seen tons of Press brakes over the years.


          • #6
            How much of 1/4" plate can I bend with a 3/16" apron brake.

            I have no clue and can of no help except positive encouragement. I say experiment a little at a time.


            • #7
              Since bending stiffness is a function of the cube of the thickness of the material, the 1/4" plate is about 2.37 times as stiff as the 3/16" plate. So, you should be able to bend about 4.25 feet of 1/4" plate and keep the loading on the brake about the same. However, as mentioned before, you have to be sure you can get the "toe" of the clamp far enough back that you don't damage the clamp. Also, consider that the loading in the clamp is more concentrated than if you had a full length piece in there. I think you can get away with it but I wouldn't recommend doing it as standard practice.


              • #8
                I agree with Dobermann, I have a 14' x 3/16" same brand that produces a slight bow in the bend. It's not a problem for what we do. I'm concerned about all that pressure in a short length. I'm sure ours has bent 1/4" before I got it. But it was put into service in 1947 so maybe it's normal wear and tear.


                • #9
                  Wow, Ive never heard of a 14' leaf or apron brake, I'll have to start checking.


                  • #10
                    T Red, Chicogo Dreiss krump sent me a list of brakes and they dont show a 3/16" x 14'-1", the sizes they show on the list I have are 1/4", 3/8", 1/2" and 3/4", they have them in those sizes up to 16' across as well, so I wonder if your brake isnt a 1/4".


                    • #11
                      We finally got the brake to the shop pulling it with my New F-250 6.2 gasser, the trailer weighs about 4,000, the brake was 11,500 with the hydraulic unit that powers the raising and lowering of the head, the truck weighs 7,000 so my total load was about 22,500 lbs.
                      Towing it back from Chicago was about a 240 mile trip each way at 7.5 miles per gallon on the way back.

                      I've gotten conflicting opinions about how far the head needs to be set back, Most people say 2XX material thickness to keep the apron from binding.

                      Its really nice not having to depend on other people every time I need to bend something.

                      ​I've had a 18" brake in my 50 ton hydraulic H Frame press which allows me to bend 1/2" thick material which has been a life saver but


                      • #12
                        why are my posts not going through


                        • #13
                          Take the time to post up a couple pics.
                          Its really nice not having to depend on other people every time I need to bend something.
                          You prolly got it at the right price which helps. .
                          My redneck engineering says to go a size thicker or 25% than recommended would take 2x so 5 ft at best.

                          Last edited by Sberry; 10-13-2015, 05:32 PM.


                          • #14
                            I got it for $ 9,500.00, I did a 5' of 1/4" plate with the head set back 3XX material thickness without a problem, the only problem is, when trying to make a channel, the longest one of the legs can be is about 2-1/4" because when you clamp the head down, the head hits the leg if its taller than that.

                            Are there any tricks that I'm not thinking of.


                            • #15
                              Sberry, I got it down to $ 9,500.00., Why is there such little info on Apron Brakes, I love this thing, my wife is getting jelouse because I have been out in the shop spending more time with my 11,000 lb girlfriend than her.

                              What happened to these old dinosaurs, there are lots of press brakes for sale but big apron brakes are far a few between.

                              I go into miscellaneous shops all the time, but have only seen one shop in my 26 years of business that have one that will bend more than 14 ga.