METALWORKING GLOSSARY
Arc
The bend degree or angle of the curved portion of a piece of pipe, tube, or beam.

Bevel
An angular cut around the outer diameter (OD) or inside diameter (ID) of a tube end. The bevel allows a piece of tube or pipe to fit into and be welded to another piece of metal.

Box Depth
The maximum height or depth of a metal pan.

Center Line Radius or CLR
The distance from the center of a pipe’s curvature to the centerline (axis) of the pipe. The CLR is expressed as a number multiplied by the tube or pipe size. For example, the bend radius of a 5 x D bend for a 2-inch nominal pipe size (NPS) pipe or a 2-inch tube is 10 inches.

Cold Bending
Using cold shaping methods to bend a piece of pipe, beam or tube. In other words, in cold bending, only force, not heat, is used to change the shape of the material.

Distance Between Bends or DBB
The minimum length of each straight section between bends.

Degree
The angle at which a bend is formed, e.g. 45°.

Degree of Bending (DOB)
The maximum angle of each bend.

Easy Way
Bending of rectangular tube with its short side as the plane of the bend, requiring less force than the long side.

Elliptical Radius
A slightly elongated or egg-shaped radius of material after being bent.

Flash Weld
The welded seam on pipe or square tube materials.

Hard Way
Bending of a rectangular tube with its long side as the plane of the bend, requiring more force than the short side.

Index Point
The start point or the beginning point of reference.

Inside Diameter or ID
The distance across the center of the opening of a tube, pipe, or coil.

Material Grade
The manufacturer’s specification of material for pipe, beam, or tube.

Neutral Axis
A measurement of distance along the midpoint in the tube wall thickness. It is different from the circumference, because it is not measured around the outside of the tube but around the tube from a point in the very middle of the tube wall thickness.

Outer Diameter or OD
The measurement across the center of a tube, pipe, or coil, from one outer edge to the other. In other words, the outside diameter of a tube or pipe.

Pipe
Round material measured by its inside diameter (in contrast to tube, which is measured by its outside diameter). Pipe wall thickness needs to be added to obtain outside dimension.

Plain End
Square cuts made to a tube, pipe or beam prior to bending.

Plane of Bend or POB
The orientation of a bend in relation to the axis of the straight section preceding it. Used specifically for changes of plane in successive bends. A bend in relation to the axis of the straight section preceding it.

Out of Plane
When the horizontal plane of a single bend deviates between its tangent points, based on the theoretical centerline of the bend.

Ovality
The distortion of tube or pipe from its circular shape, caused by bending.

R Axis
The vertical motion of the back gauges.

Roll Past
The degree or fraction of a degree that beam, tube, or pipe is bent beyond a specified point.

Rough Cut
Pipe, beam, or tube end cuts that are not required to be straight.

Square Cut
End cuts to a tube, beam or pipe that are square to the centerline of a bend after the bending process.

Tangent
A straight portion of material on either end of the arc of a bend.

Tangent Point
A point where the bend of a pipe, beam, or tube begins or ends.

Taper Bore
A milling or grinding out of the inside diameter of the end of a bend to create a tapered tube or pipe diameter.

Tonnage
The amount of force or pressure being produced or the ability of a machine to regulate that force or pressure. Modern hydraulic brakes can control their tonnage very accurately.

True Radius
The original shape retained by material after being bent.

Tube
Round material measured by its outside dimensions.

Wrinkles
Ribbed or wavy indentations in the inner bend angle of a bend in a piece of tube, pipe, or beam.

Wall Thickness or WT
The width of the material wall of tube or pipe.

X Axis
The axis or plane of front-to-back motion.

Y axis
The axis or plane of vertical (up-and-down) motion.

Z Axis
The axis or plane of left-to-right motion.