BENDALLOWANCE

Sheet metal: the length of a bend, measured along its neutral line, for a flat pattern.

Syntax

BENDALLOWANCE(angle,R,K,T)

Argument	Meaning
angle	How far the bend turns, in degrees (90 for a right angle).
R	The bend's inside radius.
K	The K-factor: where the neutral line lies through the thickness, from 0 (the inside) to 1 (the outside). About 0.44 for mild steel.
T	The sheet's thickness.

Result

A number: angle (in radians) × (R + K × T).

Examples

Expression	Gives
`BENDALLOWANCE(90,2,0.44,2)`	`4.524`
`BENDALLOWANCE(0,2,0.44,2)`	`0`

A flat pattern measured to the bends' tangent lines adds a bend allowance for each bend. A sheet-metal drawing started from File › New (see Materials) has T, K and R for its material, so BENDALLOWANCE(90,R,K,T) follows the material chosen.

Notes

It is an error if R or T is less than 0, or K isn't from 0 to 1. The angle's sign doesn't matter: -90 is taken as 90.