Bending Sheet Metal Part 1

[@throngcleaver]

Great video! Twenty years ago, while working for a major military aircraft manufacturer as a flight mechanic, when one day,I was tasked with a huge stack of drawings of sheet metal parts, to build for various fight test aircraft. I hadn't bent sheet metal in the previous 15 years, since leaving A&P school. Many of the parts had multiple bends, some had two or more radii sizes, and some had bends that weren't parallel to each other. It was a daunting task to utilize the company's engineering handbook, in which huge tables of various angles, (in 5° increments) had to be cross referenced to the thickness, and so on. After a few hours of ciphering on the first piece, I was already sick of all the math. And I LOVE math! For instance, a bend might have been 63°, but the information in the tables was only there for 60° and 65°, so some math had to take place. Not a big deal for one or two bends, but I had dozens of bends to calculate. These weren't simple 90° angles, or hat sections. So, I went to one of the computers and opened Excel. I put the interpolation formula in there and could easily type in the 3 numbers I needed to get the answer. That would save me some time, but figuring the setback and adding up the flanges was still going to take more figuring. It wasn't long before I figured out that I didn't need to do ANY math. I simply put the bending formula from the engineering handbook into Excel. So, from then on, all I had to do, was to open that spreadsheet, type in the thickness of the material one time, (since I've never had to bend tapered stock) type in each bend angle, type in each bend radius, type in each flange length, and hit enter and everything is calculated instantly. I set it up for 4 bends, to be able to do a hat section. I included a drawing in the spreadsheet with the distance from the edge of the part to each bend line, and the information showing the length of each flange, the radius of each bend, and the angle of each bend, so that when I had cut my flat pattern, and drilled and countersunk all the holes in it, (even the holes for the nutplates) all I had to do was take my part to the press brake, install the correct die set, zero the back gauge, (w/digital readout) and bend each flange to the correct angle. Every bend was accurate to within 0.001" in length of that flange. Parts clecoed together perfectly. I also added the bend tangent formula, for certain jobs that required that information. Eventually, word got out and everyone wanted a copy of that spreadsheet. I used it to make thousand of parts in my personal business, until I finally got SolidWorks.

[@tedfarwell9812]

Very good explanations in well-produced video. Nice expansion of Sport Aviation article. Looking forward to second part.

[@legionjames1822]

Mat thickness÷3+radius×degree× .01745=bend allowance. Bend allowance is the rough adjustment to the blanks size. K-factor is a very fine adjustment. You can use .45 k-factor without causing any trouble.

[@caspernilsson]

Such a well made video! Thanks for doing this.

[@gordon6029]

A very well produced video. Thank you

[@1lapdown]

I watched this video a couple of times to be sure I had understood the theory and the math. I think you could take the pace of the video just a little slower but that is just for me. Re watching it helped a great deal. Nicely done!!

[@RainbowAviation]

I appreciate feedback.

[@Z-add]

Use the youtube buildin playback speed option and slow the video down. It might help.

[@KowboyUSA]

This is useful information. Thank you very much.

[@ZimmMr]

So clear! Thank you!

[@legionjames1822]

Radius is set by your material tickness, not top die. Unless your desired radius is larger than you material tickness.

[@ronlaury6388]

Great series! Any chance to get a printed copy of this article or a .pdf document ? Sure would be a get asset to my library,

[@kevinault9419]

Use Solidworks