Bending angle iron the "hardway"

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I posted a question on bending angle the "hardway" with a cheapy pipe bender in the welding area and got only one response so I thought I'd better move over here.  After calling around to all of the local "pro" fab shops no one could bend it so with knowledge gained from other posts on here I went for it and after three tries had a duplicate curve off of the old snow plow!The details if anyone cares:  $99 pipe bender out of Northern Tool catalog to Bend 1 1/2" x 1 1/2" x 1/4" angle into a radius of about 9 inches over 3 feet.   Used the 3/4" pipe die removed the stock rollers and used 1 1/2" square tubing with holes drilled for the pins.  Screwed a scrap of 1" material through the existing holes in one side of the frame.  Cut relief cuts every inch for six inches from the center of the angle and pounded in a 2x6 scrap on the back side to keep it all tight and then bent until the curve matched.  then welded the gaps shut and ground smooth!  Here are some pics thanks for all the knowledge! Attached Images
Reply:The three pieces of angle in the previous post are the trials the first was uncut and didn't bend clean and wanted to twist.  The second was with kerfs cut every three inches from the center The first three cuts were the only ones that moved and the curve is not smooth and welding and grinding of all the non used kerfs would have been time consuming the third one is the keeper.  The finished plow shown here ...the curved piece is toward the front with the white grease on it.  Everything black is new the red is old. Attached Images
Reply:Oh, you wanted to bend it with the flange out!!!!   Yeh, they make a cheap bender for that, it's pretty easy!!!!      Nah, just kidding. Good job. That's the way it normally gets done unless you want to use a torch. For small one time applications like that one there you do whatever gets the job done.
Reply:Actually, I would call bending it flange out, the easy way. Because you are asking the flange to stretch, and its easier to stretch the angle than to shrink it. You can also bend it on the axis of the "V", both flange in and flange out- so when you end up, either the inside of the curve, or the outside, has a diamond shaped profile. Lots easier to do this with a hossfeld bender- you dont need to cut the slits, or weld em up again. My hossfeld will bend angle flange in or flange out, cold, pretty easily.
Reply:Dichdoc good work,  just sharing informations for others who might read this.  When I notch to bend I usually notch on the inside of the bend.  The gap closes up, thus leaving less to weld.       I used to make a cut then close the gap then cut again.  For a curve I would make make several cuts at regular increments and continue to cut and close until I got the shape I wanted, then weld the notches.  A chop saw works best because of the wide kerf.    I used this technique for patterns when I was doing a curved railing.  However, I stopped doing it when I figured out that I could bend it cold and actually use the piece I initially bent.  I have done it on tubing to make no measure miters, also.  Though mitering tubing takes practice because of how the tubing changes shape as it is cut. I am sure everyone remembers Conic sections in Algerbra 2/Geometry.
Reply:Originally Posted by tapwelderDichdoc good work,  just sharing informations for others who might read this.  When I notch to bend I usually notch on the inside of the bend.  The gap closes up, thus leaving less to weld.       I used to make a cut then close the gap then cut again.  For a curve I would make make several cuts at regular increments and continue to cut and close until I got the shape I wanted, then weld the notches.  A chop saw works best because of the wide kerf.    ...
Reply:coach,a lot of the time its just by guess and by golly! If its a large circ., the notches can be farther apart, small arch,closer spaces. No need for a "V" cut if using the chop saw because the blade slice is 3/16 or so. When you bend your many notched piece, the tips of the cuts hit leaving you a triangle shaped hole to weld.
Reply:When you bend your many notched piece, the tips of the cuts hit leaving you a triangle shaped hole to weld.
Reply:I kinda forgot to add that part Sandy,  thanks for the assist
Reply:There is a mathematical way to determine the number of notches it will take.  If you needed to be precise you would need to determine the diameter of the circle you are trying to make (I know you are only making an arc but you need figure as if it were a circle).  For example if the inner diameter were 48” and you had 1” angle iron the outer diameter would be 50”. Use the formula C=pi*D (pi is aprox.3.14)  and you get an inner circumference of  150.7”and an outer circumference of 157“ . This means you will have to cut 6.3” of nothces on the inside edge of the angle iron to make a circle. Since you are only making an arc you will need to know what portion of the circle that you are making. If it were a 90deg. Arc or ¼ of a circle then you would need to remove 1.575” of material. Divide that by the kerf of your chop saw to get the number of notches. Space them evenly and bend. The more notches the smoother the curve, picture a triangle – square – pentagon – hexagon – octagon – etc. , the more angles, the closer it gets to a circle .  .Me - I'd wing it - cut a few notches and see how it goes .
Reply:Yeah, keep it simple.  I usually like Tek wrote determine the size of the arc and cut notches accordingly, e.g. small arch more notches large arch fewer notches.  Cool description Snobound-more notch smoother curve.Just kidding about the Conic Sections stuff.  However, if you do use this technique for mitering, then I usually determine the angle, say 30 degrees, then draw a line where I want to bend, Then cut a 15 degree vee on each side of the line.  This makes both sides equal when they are closed for welding.  If the pieces are or not equal then they will not match when closed up.  It is like putting a 45 degree cut and a 10 degree cut together and expecting the edges to match.I sometimes use the mitering technique for forming the easement on step rails. The easement is the place where the step rail runs parallel to the ground/porch and attaches to the guard rail.Last edited by tapwelder; 01-11-2006 at 09:52 AM.
Reply:Being in the hvac business I do alot of radius bends.I use light guage angle say 24 guage notch it with my tin snips and bend it the way I want it then once I got it perfect straighten it and scribe it on my angle to be bent and notch it with my grinder then go for lunch.....lol job done!!!Nobody moves nobody gets hurt(safety first)millematic passportmiller 375 plasmacutter
Reply:I've seen some pretty impressive results with torch bending or cambering.