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Trades & Professional Tools · Welding & Metal Fabrication

Sheet-Metal Bend Deduction Calculator

Calculate outside setback and bend deduction from entered bend geometry and K-factor.

Trades & Professional Tools · Welding & Metal Fabrication

Enter your project measurements

Measured inputs · visitor-entered product and design assumptions
  1. 1EnterProvide the known values
  2. 2CalculateResults update automatically
  3. 3VerifyReview the details and units
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Use verified measurements, machine or vehicle data, qualified procedure values, field cycle observations, and the stated coordinate or unit convention. Values stay in this browser.

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Understand the job

What the Sheet-Metal Bend Deduction is for

Calculate outside setback and bend deduction from entered bend geometry and K-factor.

Flat-pattern calculations connect inside radius, angle, thickness, neutral-axis convention, tooling, grain, springback, and flange geometry.

Simple visual explanation

Follow the calculation from field input to decision

Define finished geometry
Apply bend convention
Check flat pattern and tooling
Each stage is deliberately separate: verify the source values, the calculation basis, and the final field or shop check.
Bend angle through material (degrees)Inside bend radius (mm or in)Material thickness (mm or in)Entered K-factor (0 to 1)

The relationship

Read the formula before using the result

Outside setback=tan(angle/2)×(inside radius+thickness); bend deduction=2×setback−bend allowance.

The calculator preserves full internal precision. Confirm that every entry uses the same measurement condition, unit basis, product or machine data, and scope represented by this formula.

Professional check

Turn the answer into a responsible next step

1. Verify the inputs

Use actual measurements, current drawings, approved specifications, and manufacturer or process data for the real job.

2. Challenge the assumptions

Check allowances, losses, stock or package rounding, operating condition, and whether the result matches an independent measurement or estimate.

3. Respect the boundary

It does not create or qualify a welding procedure, accept a weld, select safe parameters, approve a joint, set exposure controls, or replace drawings, standards, inspection, and qualified personnel.

Quick guide

How to use this calculator

  1. Choose the calculation mode or measurement system that matches the values you actually have.
  2. Enter measured project dimensions and use product-specific coverage, density, yield, resistance, or waste data where requested.
  3. Review the intermediate results before ordering material or applying the result on site.

Calculation method

Calculation method

Outside setback=tan(angle/2)×(inside radius+thickness); bend deduction=2×setback−bend allowance.

The calculator preserves full internal precision and rounds only displayed results. Quantity outputs round up when whole purchasable pieces are required.

Worked example

Worked example

A 90° bend with 2 mm radius, 1 mm thickness and K=0.4 has 2.230 mm bend deduction.

Outside setback=tan(angle/2)×(inside radius+thickness); bend deduction=2×setback−bend allowance.

Supported inputs

Precision and limits

Qualified process and machine-data boundary

Use the qualified procedure, manufacturer cut chart, measured kerf, verified material data, machine limits, ventilation, guarding, interlocks, PPE, and approved production controls for the actual process. These calculators do not establish a safe laser or welding procedure, exposure limit, eyewear, weld acceptance, machine setting, or material compatibility.

Planning scope

This calculator supports measurement, estimating, and scenario planning. It does not inspect a site, select a product, certify a design, or replace drawings, specifications, manufacturer instructions, local codes, permits, or a qualified trade professional.

Measured and product-specific inputs

Nominal dimensions can differ from actual dimensions. Verify inside pipe diameters, actual lumber sizes, product coverage, bag yield, material density, conductor resistance, waste, and packaging against the materials used on the project.

Safety and regulatory limits

Electrical, HVAC, structural, excavation, roofing, pressure, lifting, and life-safety work may require jurisdiction-specific calculations and professional approval. Do not use a generic planning result as a code-compliance or safety determination.

Precision and privacy

Inputs accept bounded plain decimals. Calculations remain in this browser and raw entered project values are not submitted to 365CALCS.COM.

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