Bend deduction formula The formula uses the same parameters as the bend allowance equation: BD=2⋅(r+T)⋅tan(θ2)−BABD=2⋅(r+T)⋅tan(2θ)−BA 🙋 While we don't need a 90-degree bend deduction chart to estimate the bend deduction for that type of bend, it is alwa...