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One-bend K-factor arithmetic

Sheet-metal bend development

Inputs

Included bend angle in degrees for the one stated bend.
Nominal inside bend radius.
Nominal sheet thickness.
User-entered neutral-axis ratio; this screen does not select it.
First stated outside-to-apex flange length for the one-bend model.
Second stated outside-to-apex flange length for the one-bend model.

Results

Bend allowance

4.1312

Outside setback

3.5

Bend deduction

2.8688

One-bend flat-length estimate

87.131

BA = (π/180)B(IR + K·MT); OSSB = tan(B/2)(IR + MT); BD = 2OSSB − BA; Flat = L₁ + L₂ − BD

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Nearby: Milling removal rate · Drilling speed & time · Turning material removal · Milling cutting parameters

Method

Formula, when it applies, and when it does not

Calculate bend allowance, bend deduction, outside setback, and a one-bend flat-length estimate from sheet-metal geometry.

BA = (π/180)B(IR + K·MT); OSSB = tan(B/2)(IR + MT); BD = 2OSSB − BA; Flat = L₁ + L₂ − BD

When

  • One bend
  • User-entered K-factor
  • Nominal geometry
  • Flat length from stated flanges

Don’t

  • This is nominal one-bend K-factor arithmetic with user-entered inputs. It excludes K-factor selection, bend-radius rules, springback, tooling, grain direction, forming method, material condition, tolerances, bend relief, multi-bend sequencing, collision, and manufacturing qualification.
GoEngineer sheet-metal bend calculation guide