Metal Fabrication Resources by Blackstone Advanced Technologies

Blackstone Advanced Technologies Blog
Dec 12, 2018 3:33:00 PM

Sheet Metal Design Considerations: Maximum Amount of Bend

sheet metal design considerations

In order to understand what the maximum amount of bend is for certain gauges of sheet metal, it's essential to understand a few basics of bending and other terms involving metalworks.


Let's take a look at everything you need to know about this particular sheet metal design consideration and understand what the maximum amount of bend is for certain gauges of sheet metal.


Sheet Metal Design Considerations: Bending, Radius, and Metalworking

For the purposes of this piece, "bending" refers to the process by which metal is manufactured to the point that along a straight axis, it produces a

  • V-shape

  • U-shape

  • Channel shape

Box and pan brakes, and other brake processes, are most often used for bending.


"Bend radius," meanwhile, is the term used to describe the radius of the inside curvature of previously bent sheet metal. It’s the minimum radius that a pipe can be bent or otherwise compromised without getting:

  • Kinked

  • Damaged

  • Otherwise having its useful life shortened

Sheet Metal Bending: Minimums & Maximums

It stands to reason, then, that the thicker and harder the plate is, the larger the minimum bend radius is. However, finding the true minimum bend for a steel or an aluminum plate requires a bit of thought (and, in some cases, trial and error).

1. Sheet metal plates run about 0.005” to 0.249” in thickness.

2. Aluminum and steel plates, on the other hand, start at about 0.250 inches in thickness, and can go as high as 13 inches in thickness.

According to fabricator Steve Benson, there's a simple mathematical equation to determine a minimum (and maximum) bend radius for both sheet metal and aluminum and steel plates. Follow these steps in order:

  1. Divide 50 by the material’s tensile reduction percentage.

  2. Subtract 1 from that answer.

  3. Multiply that answer by the plate thickness.

The end result will give you the minimum inside bend radius. The maximum bend radius, meanwhile, has an equally simple equation: add the minimum bend radius to the part thickness, and multiply the result by 2.


For More Information ...

For more free information on sheet metal sizing -- including several useful charts categorized by material -- click the graphic below.


As sheet metal fabricators trusted by no less of an authority than the U.S. Navy, Blackstone Advanced Technology is here for all your sheet metal needs. For more design assistance, contact us today. (We also do free engineering consultations!)

sheet metal size charts