Home built tubing roller.

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I am nearing completion of a tubing roller that I have been building for a few months now. Here are some pictures of it so far. Just cant seem to figure out how to keep the center roller which applies pressure to stay level with the other rollers. (when I apply a lot of pressure, the back take up bearing goes down and it rolls square a little crooked) I am still trying a few different things, but I don't have any good ideas so far. Attached Images
Reply:Looks good!I have been slowly working on a roll bender as well. I think your problem is the center set of bearings are riding in a small slot that needs to be much bigger. They need to ride in a "T"-slot essentially. That is how the big ones are designed.Mine is made out of 1" plate and in each plate, there is a t-slot (that supports the center bearing). The t-slot dimensions are 6" wide x 8" tall and the overall thickness of the sliding t-slot is 1 1/2" thick. My bearings are 110mm OD with a 50mm bore just to give you an idea of material. I have over-engineered mine specifically to avoid the problem you are describing.Your construction looks good and is very similar to what I want to do. I have a 5hp 3ph motor and a boston gear reducer. I just connot find time to work on mine!http://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything
Reply:ANother thing I forgot to mention is your t-slot design needs to be a VERY close fit up. The surfaces need to be machined to a fairly close tolerance in order to remove any slop in the vertical plane.Granthttp://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything
Reply:Pulling the roller down with a yoke rather than pushing it would help, but that would require a redesign....My name's not Jim....
Reply:Scratch that,  I didn't wait for all the pics to load.  The way I see it,  easy solution is one tensioning bolt for each bearing.  Then you can compensate for shaft flex and such.  Those self aligning bearings aren't really helping ya.  And what Jackalope said makes sense also.My name's not Jim....
Reply:If you look at your design, you cansee the inherent flaw with the center die guides/assembly. You are pushing down on the center (with your acme threaded rod). This puts direct pressure squarely over the center of the shaft in the assembly. Under NO load, NO problem. Put a die with a piece of tube in there and the tube begins to act like a pry bar on one side, thus throwing off the smooth up/down and side to side movement.When I design things, I try to over-exagerate the dimensions in each direction in order to help me make up a better design. So, essentially, the only way to eliminate the problem you are experiencing is to either exert two downscrews simultaneously (which is not possible as the die is on one side) OR figure out how to exert this equal down pressure by making a very large t-slot as I mentioned earlier. You need to also design a way to tie the moving bearing assemblies TOGETHER other than by the shaft itself. This is allowing the bearing assemblies to move independently.You basically need to just beef the entire center roller/ assemblies up and together.I am sure you did some research before building yours because it looks as though you did. Go back and look at a Baileigh or Ercolina roll bender and you will see exactly what I mean. You will have the "ahh haaaa"moment! Everything else looks very good.http://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything
Reply:It might take a bit of rework but why not use 2 acme rods to push down.  One at each bearing block.You could tie the 2 together by gear or roller chain.  (The gear method would require left and right hand acme rods.)  It would have to stay level.
Reply:The sell one of these at Harbor Freight.. http://www.harborfreight.com/cpi/cta...emnumber=99736It gets around the issues your having by passing the material between the sides of the bender so everything is supported on both sides...  $159 isn't too bad. I have 1 and it works pretty well.  I do like your drive setup though.Do you have any links to the motor and gear reduction box you used?
Reply:Jeep, this machine you refer to is a POS. Will not work for the application of bending larger tubing.Die changes are next to impossible for the design you mention as well. For a simple ring rolling application it is fine, but not beyond that!And for the OP, you need to get rid of one of these threads! You have two identical threads in two seperate forums!!!!http://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything