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# Bend Deduction - right angles

## Description

Bending is a manufacturing process that produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials, most commonly sheet metal. Commonly used equipment include box and pan brakes, brake presses, and other specialized machine presses. Typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork.

The bend allowance (BA) is the length of the arc of the neutral line between the tangent points of a bend in any material. Adding the length of each flange taken between the center of the radius to the BA gives the Flat Pattern length. This bend allowance formula is used to determine the flat pattern length when a bend is dimensioned from 1) the center of the radius, 2) a tangent point of the radius or 3) the outside tangent point of the radius on an acute angle bend.

The outside set back (OSSB) is the length from the tangent point of the radius to the apex of the outside of the bend. The bend deduction (BD) is twice the outside setback minus the bend allowance. BD is calculated using the formula shown.The formula works only for right angles.

Related formulas

## Variables

 BD bend deduction(deg*m) (dimensionless) R inside bend radius(m) (dimensionless) T material thickness(m) (dimensionless) A bend angle (the angle through which the material is bend)(deg) (dimensionless) BA bend allowance(deg*m) (dimensionless)