Bend Allowance is often confused with Bend Deduction- it is important to understand which value you intend on working with. Once you understand what these values represent you can use them to accurately and quickly develop flat patterns for your sheet metal parts.
Sheet metal bending is not always going to be the same with every application. The largest variations come from the materials themselves. This chart will get you close enough for most applications and may not require fine tuning on your part, however if you are truly dedicated to precise bending, download the excel sheet and begin plugging in your own values.
The below chart is for even numbered gauges 8 through 24 and has a default K-Factor of .33 for each. The inside radii are based off of a standard Air Bend Force Chart. You can easily modify the Material Thickness, Inside Radius and K-Factor for each thickness at the top of each column.
Press Brake Bend Allowance Chart
Bend Allowance Chart- pdf printable