Min Bend Radius Calculator

Determine the smallest safe inside bend radius for your material and thickness before the outside fibers crack.

Bending too tight cracks the outer fibers. The minimum inside radius is a multiple of thickness that depends on the material’s ductility and bend orientation relative to grain.

Bending across (transverse to) the grain allows a tighter radius than bending along it.

Formula: Min inside radius ≈ k × Thickness (k set by material & grain)

Worked Example

  1. Soft aluminum may allow k ≈ 0 (near-zero radius); a hard temper may need k ≈ 3.
  2. For 0.060 in stock at k = 1, hold a minimum inside radius of about 0.060 in.

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