Rebar is a solid steel rod varying in thickness from 3/8 inch to several inches in diameter. It has a special design incorporating a raised diagonal pattern over its length. Wet concrete will form around the pattern and prevent the rebar from removal. The steel rods reinforce the concrete. Bending rebar is necessary when forming curved or special concrete shapes. A good rebar bending tool can speed up any concrete job.
Material for a Rebar Bender
You're making a long lever to fit at a right angle to the rebar and work in a bend of any radius. Buy a length of 1-inch threaded pipe able to receive a fitting on at least one end. Also buy a 1-inch threaded T connector and pairs of 1-inch threaded pipe in 2-inch, 4-inch, 6-inch and 8-inch lengths. This device will bend rebar up to about 7/8 inch in diameter. The odds are pretty slim, though, you'll even bend anything larger than 1/2-inch rebar. Anything larger is a major industrial construction application.
Building the Rebar Bender
Screw the T connector onto the 6-foot length of one pipe with the middle threading.. Screw whichever pair of shorter 1-inch pipe you want to use into each of the T connector's two ends. Different lengths of pipe will create different radii of bends in the rebar. Using no extensions will make a very short sharp radius. The 8-inch pipe, extending over 18 inches including the width of the T connector, will make broad open-radius bends. Change the short pairs of pipe extensions as needed.
Using the Rebar Bender
Mark on the rebar where you want the bend to start. Place the rebar on a solid surface such as a shop floor, concrete surface or asphalt street. Try not to bend the rebar on a loose or soft surface such as gravel or soil. If that is all that's available, place the rebar on a brick, stone or piece of wood.
Slide the short length of the T onto the rebar to your mark and hold the 6-foot pipe in your hand with the T connector and rebar firmly on the hard work surface. Pull back gently on the rebar until it bends. Use the tool to "walk" the rebar bender around the desired curve you want, pulling back on the handle repeatedly. Do not pull hard and try to get a bend in one try; you may crack the rebar instead of bend it. You want to use the tool to bend the rebar in small increments and repeat the process in the same area several times. Repeat this often enough and you can bend rebar in a complete "U" shape or all the way around in a 360-degree bend and circle the rebar.