Bending a spiral

Hi, i recently found this nice article about how to make a spiral staircase using a tube bending machine.

For stair handrails it is advised to use a box section, for instance a semi-circular profile.

Start by setting up the machine measuring the radius of your staircase: the machine uses a series of drive rollers that are set out to achieve a degree of pipe bend required.

The pipe is pulled through these angle rolls and then made into an arc.

Here you can find more about his article:
http://www.mustknowhow.com/index.php/mustknowhow/how-to-bend-handrails-for-spiral-staircase