Bend Metal for DIY in a Reasonably Accurate Way

There are a bunch of ways to bend metal for a bracket. Do a search on YouTube and you’ll likely find several techniques. Well, we don’t want to dis any of those because they all have a place. Yet, we will throw in another — one that is especially nice if you need more than one similar bend.

I love production parts with perfect bends even in thick material. I love to see videos of progressive dies stamping out perfect parts. Oh, but there is so much NRE (Non-Recoverable Expense) in those machines! Actually, in large volume, stamping is one of the cheapest ways to produce parts. However, DIY is not large volume.

The paradigm of production doesn’t work when you only need a few. While there are nifty mechanical bending machines for building just one (or a few) of something, those are typically big, and expensive. Well, I have a lot of tools, but like most DIY, I don’t have the room (or the cash) for big specialty tools collecting dust. That means DIY has to get creative! It’s Solutions! we’re looking for.

DIY Metal Bend Video

As mentioned above, there are lots of DIY methods to bend metal. Thick and thin. This is one more to keep in mind. When it fits your need, it can be pretty convenient. It’s not production, and it’s not super high quality, but it’s pretty fast (once you get it set up), and it’s great for DIY (especially when you need to make more than one). Enjoy the video.

The video explains several attempts with other techniques, like with a vise and hammer, also. I even tried the Slit / Bend / Weld method — (see the photo below) which turns out pretty well. Explanation in the video also tells why those other methods to bend metal didn’t really work for this job.

A Way To Bend Metal — A reasonable attempt using a Half Cut / Bend / Weld Fill technique for the bracket.

This application for metal bending is just a little different, so the requirements are also a little different. While the technique is not unique, it’s probably not the first to come to mind. Oh, and you do need a press to make it work. This one uses a hydraulic press, but (depending on your bracket) a stout arbor press can work too.

A Deeper Look

There are a couple things to note about the specific brackets in the video:

The metal to bend is 304 Stainless Steel. It’s a pretty common material in sheet stock, but it’s hard to machine and somewhat hard to bend.
These pieces are water jet cut by a local shop, Precision Waterjet, but they don’t do bending. There are other shops that do it all, but they are a lot more expensive with longer wait times. I made a few extra for bending experimentation. While this is a nice method, it doesn’t really matter how the metal is cut.
In the final installation, the brackets will hold a fair amount of force around the bend, so they can’t be wimpy (like cutting half way through then bending). Strength is important, and that’s why they are reasonably thick.
All the parts for the “die” are just bits from the scrap bin. The only parts with process are the 2 that tack weld together. While it worked with my scraps, you may do it different.
This is the press in the video, and this is the jack for motivating force.

To some, this might be over-kill to bend a metal bracket. I get it. To others, it’s out of the question because they don’t have access to a press. That’s OK too. I don’t make brackets this way very often because most of my brackets don’t need this kind of repeatability. In this case, I need to bend 4 metal brackets, all the same, and semi-professional looking.

Considerations

For this technique there are a few considerations.

First, make sure you have the force generation to accomplish the task. (Press big enough to bend your metal.)
Second, set your space for the bend at least 3x the material thickness — more for greater bends. (In other words, less space for a 45 degree bend than for a 120 degree bend.) Trial and error will tell you what’s perfect.
Third, use a center press part with a rounder edge. A sharp, square edge pressing piece will cause scraping and weirdness in the bend.
Fourth, make sure there is sufficient space for the bend to occur. That nothing is in the way when the bending happens.
Fifth, find a way to make things line up to bend the way you want. You can see in the one video segment that one of the brackets was bent at an angle. If you don’t pay attention, you will bend the metal in anything but the way you want it.
Sixth, over-bend the metal just a little because it will bend back slightly when you relieve the pressure. The amount of relaxing is a property of the material you use, so different materials will bend a little differently.

The job for our brackets job includes holding the reaction forces of pneumatic cylinders. Not a big deal, but enough that the project is worth doing right. You can see in the video that there is space for the bending, and a lot of fiddling to make the bends square. So much better to make brackets that look nice and have good strength. Here’s a photo of the end result all installed and ready for action. You can also see some of the threaded rod for custom bolts in the assembly. It all works wonderfully.