There are several terms used in custom tube bending and fabricating. This blog will serve as a reference for some of the commonly used words and phrases that are called out in reference to this process. For additional information and detail, click the links within the content.
Centerline Diameter (C.L.D.): The distance from the centerline axis of the tube or pipe across to the other centerline of a 180-degree return bend. This is calculated by multiplying the centerline radius by two.
Centerline Radius (C.L.R.): Radius along the centerline of the pipe or tube to be bent. As a general rule, the tightest achievable center line radius is one times the pipe or tube diameter.
Degree of Bend: The angle, expressed in number of degrees, to which the bend is formed (e.g., 45 degrees, 90 degrees, 180 degrees). Also called DOB.
Inside Diameter (I.D): The measurement across the widest part of the inside opening of pipe or tube. The terminology used to describe inside diameter does not differ between pipe and tube.
Outside Diameter (O.D.): The measurement across the widest area of a pipe or tube, including the wall. It is important to note that the outside diameter is called out one way for pipe (schedule) and another way for tube (gauge), and can be explained more here.
Nominal Wall Thickness: the measurement between the outside and inside surface of a pipe or tube.
This information serves as the basis for most tube bending projects, and should be some of the key information included in a specification drawing sent to your vendor for tube bending or fabrication services. For more detail on what may be needed for a bending project, see 7 Tips For A Timely, Accurate Quote.