Calculator

Tooling guidelines · 247TailorSteel

Thickness (mm)MaterialBendK-factor (bend allowance)

Ri (internal): 1,88 mm
s min. leg length: 9,1 mm
w die opening: 12 mm
x (Z-bend): 13,8 mm
Bend allowance (90°): 3,99 mm
Bend deduction (90°): 3,77 mm

t2 Steel · Right angle (90°)

Ri 1,88 · s 9,1 · w 12 · x 13,8 mm

Right angle (90°) only — sharp has no fixed angle. Flat length = sum of leg lengths to the bend tangent + bend allowance, or sum of outside dimensions (OML) − bend deduction. K-factor is indicative (0.3–0.5, depending on material and Ri/t) — adjust or verify on your own machine/material.

Shop spec from 247TailorSteel Sophia, not ISO or DIN. Discrete thicknesses; an empty cell is not a neighboring row. Source checked: 2026-09-16.

If the part contains a sharp bend, use the sharp tables for every bend. A table row does not confirm availability or bendability of every alloy/temper at that thickness.

Additional check: hole or slot near the bend

Measure s and a from the outside face of the upright leg (virtual outside corner) to the sheet edge and nearest hole edge respectively. Do not measure from the bend tangent or hole centre. The sketch shows a 90° bend.

Actual leg length (mm)Hole diameter Ø (mm)a · outside face to hole edge (mm)

Minimum leg length s: 9,1 mm
Hole edge outside zone: a ≥: 9,1 mm
Hole centre outside zone: c ≥: 12,1 mm

Enter the actual leg length to compare.

Enter a valid diameter and hole-edge distance to check.

For Ø ≥ 5 mm we use a ≥ s. The source text says > 5 mm, the drawing ≥ 5 mm; this tool uses the stricter boundary. No guaranteed distortion-free minimum is published for smaller holes inside the zone.

Interruptions inside the bend zone

Sum all hole diameters and slot lengths inside the zone, including relevant end interruptions. Compare with this bend's length. The 10% maximum is an additional condition, not an exemption for large holes or a guarantee of hole accuracy.

Total interruptions (mm)Length of this bend (mm)

Enter valid dimensions (bend length > 0; total ≤ bend length).

This check covers only the selected table and distances. Allow for tolerances, tooling and collisions. Consider machining critical fit holes after bending. Hemming and special relief cuts need separate assessment.

Reference table — Steel, Right angle (90°)

Every thickness from the 247 tables for this material/bend combination, so the underlying data can be checked without operating the calculator.

t (mm)	Ri	s	w	x
0,63	—	5,6	8	7,8
0,8	1,39	5,7	8	8,15
0,88	—	5,8	8	8,3
0,9	—	5,8	8	8,3
1	1,4	5,9	8	8,5
1,25	1,42	6,1	8	8,95
1,5	1,65	7,5	10	10,65
2	1,88	9,1	12	13,8
2,5	2,41	12	16	18,8
3	2,75	12,4	16	20,1
4	3,02	17,7	24	26,15
5	3,62	22,6	30	34,65
6	4,62	29,6	40	42,9
8	8	43	60	63
10	8	44	—	65
12	7,83	56,5	—	79

* not monotonic in the 247 source table, not a transcription error here.

Section

Bend in the die: w is the die opening width, s the minimum leg length, Ri the inner radius at the bend. Dimension lines follow the selected row. Not to scale.

Cross-section · right angle (90°)

Source: 247TailorSteel — bending guidelines. Shop spec Sophia, not ISO/DIN. No commercial affiliation; always check their page (checked 16-09-2026). Collision checks, tooling photos and the A–F tolerance grid live there, not here.

Additional: flat pattern for a custom bend angle

Calculator

Bend allowance (K-factor)

BA = θ·(Ri + K·T), BD = 2·(Ri+T)·tan(θ/2) − BA. K here follows automatically from the rule of thumb Ri/T: <1 → 0.33, 1–<3 → 0.40, ≥3 → 0.50.

Note: the tool above uses a manually entered K (default 0.33) instead of this automatic Ri/T rule — for the same 90° bend the two tools can give a different number if your Ri/T ratio isn't close to 1.

Sheet thickness T (mm)Inside radius Ri (mm)Bend angle θ (° from flat; 90° = right angle)Leg 1, outside dimension (mm, optional)Leg 2, outside dimension (mm, optional)

K-factor: 0,4
Bend allowance (BA): 4,4 mm
Bend deduction (BD): 3,6 mm
Flat length: 56,4 mm

DESIGN ESTIMATE — VERIFY

Assumptions: Practical approximation, not a measured material value — calibrate on your own press brake for critical tolerances.

Source details

K-factor rule of thumb by Ri/T band (<1 -> 0.33, 1-<3 -> 0.40, >=3 -> 0.50)

Checked 2026-09-17

Loading calculation model…

Questions

Is this ISO or DIN?+

No. It is 247TailorSteel Sophia’s intake spec. Other shops have other radii and leg lengths. Open their page; this is a worksheet.

What are Ri, w, s and x?+

Ri is the inside radius after bending. w is die groove width, s the minimum leg length (overlay on the die), x the Z dimension for a Z-bend. Empty cell: not in their table.

Why is alu 0.8 mm Ri empty?+

The 247 page has a dash there. That is not a neighbour of steel 0.8 or alu 1.0 mm. Do not fill a neighbouring value.

Why the 10 and 12 mm note?+

247 notes those thicknesses cannot run the full sheet length. The tool still shows the row, with that caveat. Check the current page.

Sheet metal edge guidelines

Tooling guidelines · 247TailorSteel

Interruptions inside the bend zone

Reference table — Steel, Right angle (90°)

Section

Bend allowance (K-factor)

Questions

Tooling guidelines · 247TailorSteel

Interruptions inside the bend zone

Reference table — Steel, Right angle (90°)

Section

Bend allowance (K-factor)