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Standard Bend Sheet Radius
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September 23, 2015, 07:10:39 AM
Hello all
So here's my dilemma I use the bend sheet tool to make a C Channel part, then 6 months later I need to modify the part but I cant remember what bend radius I used for the original and now the width and depth end up being different. I usually use 1/2 the material thickness for the neutral depth and am using the same bend point as the original part and to the best of my memory I have left the radius at the default of .10, so my question is this do you have a standard radius you use for 1/8" 3/16" and 1/4" mild steel or a formula you use to calculate this, I need to start doing thing more consistently.

User Since V8, currently using TurboCAD Pro Platinum 2018.
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September 24, 2015, 01:43:16 AM
Most often, when I have to fit a particular bend radius, I am duplicating a pre-existing design (some 40-60 year old item that needs duplicating).

As for what's most common, I see multiples of 0.1" or 0.25", but it can be specified for the inner curve or the outer curve, so it's really no help to you.  Sorry.


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* September 24, 2015, 08:38:43 AM
There are minimum bend radius standards for bending sheet metal. If you use the minimum radius, in theory you won't get cracks along the bend line (assuming you bend across the grain). Always try to do your layout to bend across the grain, even if you have to skew the flat plate in your sheet stock (bends at right angles to each other). A little more waste material, but less scrapped parts. If the design allows use greater than the minimum. That's where things get hard, since now you don't have a "standard" to go back to. Of course all this is dependent on the tooling the fabrication shop has available. If it's dedicated tooling then go by the tooling. If bending on a brake, you can adjust the nose radius of the brake by adding a piece of bent sheetmetal on the nose to form the new radius. By the way, the bend radius is always the inside radius.

This link is a couple charts for minimum bend radius for different alloys http://www.bjg-design.com/designbook/shbend.htm