Bend Allowance Calculator

The Bend Allowance Calculator uses the thickness of the material, bend angle, inside radius, and K factor to find the bend allowance. 

INSTRUCTIONS: Choose units and enter the following:

• (B) Bend Angle
• (IR) Inside Radius
• (K) K Factor
• (MT) Material Thickness

Bend Allowance (BA): The calculator returns the answer in inches (in). However this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

When sheet metal is bent, the metal around the bend becomes deformed and stretched. When that metal deforms, a small amount of length is added to the original part. Deductions have to be made from desired part sizes for flat patterns to results in a correct flat size. The bend allowance is the material added to the actual leg lengths of the part in order to develop a flat pattern.

To find the bend allowance, use the formula:

BA = π/180 ⋅ B ⋅ (IR + K) ⋅ MT

where: 

• BA = bend allowance
• B = bend angle
• IR = inside radius
• K = K factor
• MT = material thickness

Fabrication Calculators and Constants

• K Factor Calculator
• Aluminum Wire Deposition Rate Calculator
• Steel Wire Deposition Rate Calculator
• Welding Heat Input Calculator
• Groove Weld Potential Root Cracking Calculator
• Weight of Hot Rolled Steel Flats
• Modulus of Elasticity for Martensitic Stainless Steel
• Brinell Hardness of Gray Cast Iron
• Bend Allowance

Welding Calculators:

• Bend Allowance Calculator: Computes Bend Allowance based on the thickness of the material, bend angle, inside radius, and K factor.
• Weight of Aluminum Square Bars: Computes the average weight of aluminum bars based on the number and dimensions of the bar, and an average density of 2700 kg/m3 for aluminum bars.
• Aluminum Wire Deposition Rate Calculator:  Estimates the rate at which a welding wire is converted into weld metal using the electrode diameter, wire feed speed, and electrode efficiency.
• Welding Heat Input Calculator: Estimates the amount of heat or thermal energy that is introduced to a material when a weld is made using the arc voltage, current, and travel speed.
• Groove Weld Potential Root Cracking Calculator: Determines whether or not the groove weld has a potential for root cracking based on the width-to-depth ratio (1.0-1.4).
• Weight of Hot Rolled Steel Flats: Computes the average weight of steel flats based on the number and dimensions of the flats, and an average density of 7800 kg/m3 for steel flats.
• Modulus of Elasticity for Martensitic Stainless Steel: The measure of stainless steel's tendency to deform elastically when a force is applied.
• Brinell Hardness of Gray Cast Iron: Measure of gray cast iron's ability to resist permanent indentation deformation.
• Weight of Brass Rounds: Computes the weight of any number of brass round bars based on the number of rods, their dimensions, and an average density of 8,600 kg/m³ for brass.

References

SheetMetal.Me (http://sheetmetal.me/formulas-and-functions/bend-allowance/)