Sheet Metal K-Factor Chart
A K-factor chart is a starting point, not a substitute for measured bend data. Material, tooling, inside radius and bend method decide the real value.
k factor chart sheet metal k factor chart bend k factor chart
Practical starting bands
- Air bending: often starts near K = 0.30 to 0.40 for many ductile sheet metals.
- Bottoming: can run higher because the bend is forced closer to the die geometry.
- Coining: can shift higher still, but setup-specific data matters.
Why charts drift
Two shops can bend the same material and get different flat lengths because punch radius, die opening, grain direction and springback are different.
Best use
Use chart values for quoting and prototypes. Use measured coupon K-factor for production flat patterns.
Related pages
- Sheet-metal K-factor calculator - back-solve K from a measured bend allowance or coupon.
- Bend allowance calculator - use a known K-factor to calculate bend allowance.
- Bend deduction calculator - convert between outside dimensions and flat length.
- What is K-factor? - neutral-axis explanation and formula context.