“Bump Bending” is when you make a series of small bends in a straight piece of tubing to approximate a rolled bend. Roll bending is the true way to make large sweeping bends in tubing. We show a roll bender in the “Bender Tech” article on this site. Start with the calculator above if you need to calculate the radius of an already existing shape (like a car roof or bumper). You can use the calculator below to figure out how many bends will go in your part and how many degrees to put on each bend!