Whether a section can take the radius on the drawing is decided by the ratio of radius to thickness, not by the machine. The calculator checks it in three seconds, before you write an enquiry.
Calculator
Indicative value for solid wood. Not an approval — binding verification happens on the tool and the first sample.
How to read the limit
With a steel strap the practical limit is about 2:1, without a strap about 5:1. The strap wraps the outer curve and stops the outer fibres failing in tension — which is why a strap allows much tighter radii.
Species shift the limit by roughly ±25 percent. Beech is the benchmark, ash sits just above it, oak needs the largest radii. Below 8 mm thickness the ratio improves, because the outer fibre is strained less.
The result is indicative. It becomes binding on the tool: the first sample shows whether the radius holds after drying or whether springback has to be corrected. More in the bent wood glossary under bend radius and springback.
Frequent questions
Why does the ratio matter more than the absolute radius?
Because the strain on the outer fibre depends on arc length relative to thickness. A 10 mm part can take R20; a 30 mm part needs R60 for the same stress.
Does the value apply to bent plywood?
No — plywood sits considerably lower because each veneer layer is strained only slightly. Ratios from 8:1 are normal for shells, tighter with thin layers.
What does tooling for a new radius cost?
It depends on geometry, not the radius alone. Tooling takes 7 to 15 days from an approved drawing; MOQ is quoted per part.
Next step: send a drawing with radius, section and quantity via the contact page — we confirm feasibility, tooling and lead time within 24 hours.