Bending 3/8 Aluminium Rod

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mcman56
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Bending 3/8 Aluminium Rod

Post by mcman56 »

I need to bend some 6063 3/8 aluminium rod in a radius around 4 1/2", just like an unthreaded U bolt. Is there a simply way to do this with minimal tooling? It will just be a couple of parts.
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Harold_V
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Re: Bending 3/8 Aluminium Rod

Post by Harold_V »

Do you know the state of the aluminum? In the O condition it's pretty easy to bend, although with little tensile strength (13,000 PSI), while in the T6 condition it's harder to bend but quite strong (35,000 PSI).

6063 is typically an extruded alloy. Are you sure what you have is 6063? I would suspect it's more likely 6061, which is the most common alloy for bar stock.

In any case, how faithful you need the bend to be will determine the best approach. If it must be exact, you'll have to play with it a little, using an undersized form to compensate for spring-back. You may also find that annealing the material will help. You can do that safely by blackening the aluminum with a torch, then heating until it just burns off. Don't go beyond, as that will melt the aluminum. Once heated, it can be allowed to air cool, or you can quench in water. Once you've done this, it will bend without issue.

Consider making a simple wooden bending fixture if the bends are critical. One end of the aluminum is restrained so it can't pull, then the free end is wrapped around a form which you would machine with a groove the size of the material. An arm that pivots on the center of the form would then drag a shoe around the rod. The shoe would have the same radius machined in to fit the rod. I've made several bends that way, with quite reliable results.

H
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mcman56
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Re: Bending 3/8 Aluminium Rod

Post by mcman56 »

I had some material from a home improvement store, Lowe's. When I looked it up on line it was defined as 6063. I would expect it to be the cheapest type available but don't know what that would be. It does not have not have be very precise. The radius should be around 2.25 not 4.5. Are there any guidelines for the amount of spring back, even gross guidelines?
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liveaboard
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Re: Bending 3/8 Aluminium Rod

Post by liveaboard »

I used a tubing bender, with very good results.
I didn't need any particular radius though.
Spring back was minimal as I recall.
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Harold_V
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Re: Bending 3/8 Aluminium Rod

Post by Harold_V »

mcman56 wrote: Wed Mar 16, 2022 8:35 am I had some material from a home improvement store, Lowe's. When I looked it up on line it was defined as 6063.
If it is extruded, you should be able to see signs. Most extrusions have parallel lines on the surface. Doesn't really matter, though, as the condition makes the difference, not how it was produced.
Are there any guidelines for the amount of spring back, even gross guidelines?
I am not aware of any, but that doesn't mean they don't exist. The problem is that the condition of the material (hardness) makes guidelines pretty much impossible, as dead soft, which could be easily bent by hand, will respond totally differently than a T6 condition. If strength isn't an issue, dead soft (O condition) is your friend.

You could get a rough idea of spring back by simply bending a length around an approximate form (any round object). I'd suggest starting with a form that is slightly less than the desired end result. It most likely won't be a faithful radius, however. In order to achieve one, you'd have to restrain one end.

H
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jcfx
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Re: Bending 3/8 Aluminium Rod

Post by jcfx »

3/8 diameter 6063 should be relatively easy to bend especially with the large radius you're bending.

Like Harold said a simple wood fixture should work fine, one thing I've experienced with 6063 is that
the temper varies along a length I've had flats and rods break when bending, but further down a length
it'll bend perfect.

The picture below is bent 3/8" 6063, I did that with my Duo-Mite bender.
IMG_7231.jpg
IMG_7231.jpg (9.38 KiB) Viewed 3915 times
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