Granted, you shouldn’t divulge proprietary material when posting, but you must give enough info. so that we understand what you are trying to do, what problems you are having or trying to solve, and where you are going with it. Write your post, then reread it, step back and ask yourself, AS IF you had never seen your details and problem before, ‘if they can’t see my equipment, if they don’t know what I’m trying to do, will they understand what I’m asking, or am I leaving out some important details?’ Can they draw only one sketch from my description, or should I reword it, so this item or that couldn’t possible be located or oriented in the wrong way? What forces, sizes, dimensions, etc. should be included for clarity? Otherwise, you leave us wanting to help, but wasting our time by having to guess what you are doing, and then giving you half-ar$$ed answers, because we can’t see what you are doing from here. There are plenty of smart people here, willing to help and give of their time, but don’t you waste their time either. They will make assumptions based on your problem description so your description must lead them to the correct assumptions. Many of the more experienced people can make many very good assumptions, quickly, based on sketch proportions, material sizes or thicknesses, etc. so you must be careful in your description or sketch not to mislead them.
My take on your problem is as follows: (1) Your die must be shaped to cradle each pipe size, a half circle in shape to match the pipe O.D. For smaller pipe sizes the die is actually a wheel with a radius which produces a bend which prevents buckling or crimping of the pipe for that dia. and various wall thicknesses. The wheel’s outer surface or rim is shaped to that pipe O.D. (2) Your lever arm “x” is a changing length as you bend the pipe around the die and depending upon how and where force “F” is applied. “x” will start at the tangent point of the pipe and die at zero force, and then start decreasing as the pipe bends. At the same time, the force required to keep bending it will be increasing, but then “F” will start decrease as the pipe starts to yield. You must also support the pipe so that it doesn’t buckle or turn to an oval in the bending process. (3) Most small pipe and bar benders have the “F” force vector applied perpendicular to the pipe at the point of its application and actually moving radially around the die wheel. Thus, “F” will be pointing at your wall at a 90° pipe bend. Thus, “x” may not change much. The force applying mechanism looks similar to the die wheel so it cradles and supports the pipe too, and “x” is a fairly small dimension to improve the pipe support situation. You can calc. the force required to start causing the pipe to yield and have a permanent bend, at the max. “x,” this should basically be the max. force req’d. After that the force req’d. should actually start dropping (at least no longer increasing) unless your system does something to radically change “x” or the way the force is applied. But, when you’ve gone to all this trouble, adding 25 or 50% to the force application system and to the entire machine to sustain these forces is not real expensive.
Google pipe bending machines and pipe bending vendors and study their web sites. You should see some of the above.
