Bending help

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spike7638

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I've got a bunch of strips of 0.190 aluminum (5052), about 3-4 cm, wide, and I need to bend them to look like this:
steps.jpeg

I've got access to a brake that can be used on stuff up to 1/8", but I assume that limit is for really tight bends. As you can see, aside from that left-most 90-degree bend, these are all comparatively soft. Can I use a brake for this by moving the fingers back away from the edge (I apologize for not knowing all the words --- I'm a complete amateur) so that the resulting bend will be 'softer'? (In my case, it'd be OK if the first bend were a bit softer as well.)

By the way, the brake is pretty heavy duty -- not the kind of thing roofers use for flashing. It looks a lot like this one:
brake-pic.jpeg

One a related note: suppose that the left-most "tab" had a 1/4" diameter hole drilled in it, pretty much dead center. If this is clamped under the "finger" on the brake, will the bend be affected at all? I'm assuming not, but whenever I assume something, it bites me in the butt, so I thought I'd ask -- my order-of-work depends on this.

Thanks in advance for any suggestions.
 
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The 1/8" limit is for full width. You should be fine with your narrow strips. The hole shouldn't affect the bend. Try a piece of scrap to verify.
 
Not sure what your tolerances are? If I were doing it, I would scribe lines where you want the bend to be on each part. As you bend each piece. put a mark or stop on the brake handle so each piece is the same. Work your way through each bend until you get your desired shape. This is not a perfect way to do this, but you can get accurate bends if you do bends for each piece, before you move to the next bend.
Have some extra test pieces!
Hope this helps a little.
Martin
 
RJSakowski said:
The 1/8" limit is for full width. You should be fine with your narrow strips. The hole shouldn't affect the bend. Try a piece of scrap to verify.
Click to expand...
Thanks --- that "full-width" point makes perfect sense, but I'd never thought of it. I'll definitely do the "scrap piece" test.
Martin W said:
Not sure what your tolerances are? If I were doing it, I would scribe lines where you want the bend to be on each part. As you bend each piece. put a mark or stop on the brake handle so each piece is the same. Work your way through each bend until you get your desired shape. This is not a perfect way to do this, but you can get accurate bends if you do bends for each piece, before you move to the next bend.
Have some extra test pieces!
Hope this helps a little.
Martin
Click to expand...
Tolerances are "within about a quarter inch" :) These will be steps for climbing up a sailboat mast. But I DID plan to mark the bends with a sharpie, and to do all instances of one bend (e.g., that first 90-degree one) before moving on to the next. Marking the brake-handle position sounds useful, too. Thanks for taking the time to think about this for me!
 
You will need to make the two inside bends first ae the outer bends will interfere with them on the brake. Make your blanks over length and trim to length after the bend and drill the mounting holes last. Blue your bend lines with a Sharpie and lightly scribe them for more precise bends. Your trial piece will determine any corrections that need to be made. I would make up a form to fit the middle sections to make sure all my bend angles were correct. I usually over bend slightly as it is easier to correct than an under bend. Check out your test piece for any stress cracking on that sharp bend. It may be necessary to anneal that bend location. I expect that you will want the two outer tabs to be coplanar.
 
A bending jig may be better for what you are trying to achieve. There are many commercially available, or you can easily make your own.
It doesn't even need to be as elaborate as this one:
 
There's also a type used in a press. You create top and bottom dies that match the profile you want, say in some flat plate, or even built-up with stategically placed pieces of angle, bar and rod welded together.

I will see if I can find some pictures of this type.....

It all depends on how many you need to make, and how identical they all need to be.

For bending aluminum this could also likely be done in a vise.

Brian
 
spike7638 said:
But I DID plan to mark the bends with a sharpie,
Click to expand...
This is a good plan. I would recommend some sort of marker, pencil, etc and not going to scribed lines — I’ve had pieces of bar start to crack right on that scribed line as I was bending them. Not something you want to think about on a sailboat mast….
 
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