2019 Latest Version Tube & Pipe Bending Common Terminology
Outside Diameter (O/D)
The measurement across the widest area of the pipe or tube*.
Wall Thickness (W/T)
The measurement between the outside and inside surface of a pipe or tube.
This is also referred to as Schedule in pipe or Gauge in tube.
Degree of bend
The angle of the bend. This is taken on the OUTSIDE of the bend.
Straights between bends
If your part requires more than one bend there will be a minimum straight length that we will require between the bends. This is also known as the clamp length. Using our tooling list, you are able to see the minimum clamp length for any size tube and the associated centre line radius bend die from our stock tooling.
Centre Line Radius (CLR)
The radius along the neutral axis of a pipe or tube to be bent. All tooling and bends are described to the CLR.
Tube is bent around a fixed radius die with a mandrel insert in to prevent it from collapsing during bending. The tube or pipe is clamped against the die and this is then rotated whilst the pressure die moves in a straight linear motion. This is the most common form of bending.
Roll Forming (Rolling)
Tube is rolled through three rolls that allow it be formed to a large centre line radius.
Compression forming is an original technique of bending tube. The tube is clamped in place and the pressure die is moved around the radius creating the bend, the opposite to mandrel bending. This method doesn’t allow use of a mandrel.