Mandrel Bent... What Does That Mean?

[pimpinprelude]

The mandrel actually goes inside the tubing and is held by a mandrel rod to support the tubing at the opposite point of the bend. The mandrel is then taken out after the bend is complete or within the last few degrees of bending. This way in the tubing being the same diameter through the straight tubing as in the bend radius. So if you started with 2" pipe and bent it into a 90 degree bend it is still 2" through the entire bend radius. basily what is does it suports the metal to it doesnt "cave in" or loose a round shape during the bend... and pressure bending is when you put a piece of metal in a shoe and u have a rammer.. and yea it rams it into shape... that whare u get the term"pressure" bending from... any other questions????