From race cars to off-road vehicles, all sorts of rides benefit from a roll bar. Bending steel tubing requires special tools and some math, but once you have some practice, it's not so hard, especially with the following basic tips and practice techniques that will make your bends more precise.
Cut off four 2-foot long sections of DOM tubing using the chop saw. These pieces are going to be used as reference parts for measuring your bends.
Mark the tubing with the permanent marker at 1-inch intervals.
Place the tubing in the bender so that there's 6 inches from the base of the tubing die to the end of the tube for extra slack.
Adjust the collar on the bender so that the 6-inch mark on the tubing is against the zero degree mark on the bender. Make sure the piece is clamped into place before you start the process.
Pull on the bending bar using the supplied handle. The tubing will start to bend as you pull, which will also move the degree indicator on the bender at the same time. This indicator is going to be how you know what angles you need to bend the tubing, so make sure you're paying attention.
Continue bending until the indicator shows 90 degrees. The tubing has a certain amount of spring-back on the steel, so pull the tubing until the indicator shows about 91 or 92 degrees.
Mark the end of the tubing at the end of the bend with the permanent marker. This point, in conjunction with the 1-inch marks you made previously, shows you how long it takes you to bend a piece of tubing.
Remove the tubing from the bender by undoing the collar on the tubing and pull it out.
Apply masking tape to the tubing where you made your reference marks. Then apply the spray paint to the bend of the tubing. This is now your reference piece for 90-degree bends. By using this piece, you can hold it up to the area you want to bend, mark the tubing appropriately and then know where to start your bends in the future.
Repeat this process for 45-degree bends, as well as any other bends you feel you may make.
Measure the inside of the vehicle using a tape measure. The roll bar should be behind the driver's seat and parallel with the B-pillars of the vehicle, which will provide the most strength. Measure vertically and horizontally, making sure to give the tubing some breathing room. Using a protractor will help you determine what angles you need for your bends.
Add the measurements together. Add about a foot of extra tubing to your measurement for some extra slack, just in case there's a problem one way or another. Cut the tubing using the chop saw.
Hold your reference tubing pieces to the corners where you will need to make your bends. Measure from the floor to the mark on the first part of the reference tubing. This measurement should be transferred to the new tubing.
Place the tubing in the bender and bend it using the instructions in the first section.
Place the tubing in the vehicle so that it's oriented where you want the roll bar to go. Since you still have tubing to bend, you probably won't be able to place the entire thing in the car, but you should be able to have the long end--the part that goes above your head--stick out a window.
Place your reference tubing against the bent roll bar so you know where to make your next bend. This is going to be your next reference point.
Place the tubing in the bender at your mark. Use the protractor on the bend you previously made. You want it to read zero degrees. Otherwise, your new bend will be out of the plane of the other bend, and the two won't line up at the end.
Bend the tubing in the bender using the same techniques you have used before. At this point, the only difference is making sure that you're bending the new bend in the direction you need it to go. A roll bar forms a "U" shape.
Remove the tubing from the bender and test-fit it in the vehicle. If you have to remove some extra tubing from one side, cut it off using the chop saw. The bar is now bent and ready for installation.
