What K-factor should I start with for 90-degree air bends?
A 0.38 to 0.43 K-factor is a common starting range for air bending sheet metal, but the real value changes with material, tooling, radius, and process.
Sheet metal
Sheet Metal K-Factor Calculator
Estimate neutral-axis location and bend allowance from thickness, inside radius, angle, and K-factor.
mild steel16 ga0.0598 in1.519 mm
Static reference
Common thickness, radius, and angle combinations
| Gauge | Thickness | Inside radius | Angle | Bend allowance | Bend deduction |
|---|---|---|---|---|---|
| 16 ga | 0.0598 in / 1.519 mm | 0.0598 in / 1.519 mm | 45 deg | 0.0667 in | 0.0324 in |
| 12 ga | 0.1046 in / 2.657 mm | 0.1569 in / 3.985 mm | 90 deg | 0.3155 in | 0.2075 in |
Interactive calculator
Sheet Metal K-Factor Calculator
Neutral axis from inside face0.0251 in
Bend allowance0.1334 in
K-factor0.4200.30 to 0.50 is a common practical range.
FAQ
Specific checks for this calculator
Can K-factor be different for stainless and aluminum?
Yes. Stainless often needs higher springback allowance, while harder aluminum tempers such as 6061-T6 usually need larger radii and verified bend data.