Intro: Sheet Metal Brake
Some times you just need a brake. I have worked in a couple metal shops and as such have gotten used to being able to bend sheet metal without a second thought. Now that I work with wood, whenever I have a project that needs a little sheet metal bending I sigh a sad breath. I am in the middle of designing a new instructable and realized that I need a break to work it our properly. There are a few other instructables here for a DIY brake but none of them were exactly what I needed.
I need to bend some sheet metal up to about 3 feet long, so it has to have some strength to it. Flat sheet metal isn't that strong, but, to bend it to 90 degrees can require a lot of force, especially over longer bends. Basically I'm using the design by Improbable Construct on his Homemade Mini Bend Brake, I'm just making it bigger and beefing it up.
Step 1: Tools & Materials
I'm lucky enough to have all the tools I needed to make my sheet metal brake, and it doesn't require anything too crazy. The material I used was all leftovers from stuff in the past, found scraps, left overs from old jobs. I never throw away good steel if I don't have to, after sitting outside in the weather all it usually needs is a little sanding and grinding to clean up nicely. Some pieces of angle iron from an old satellite dish, some flat stock from who knows where, pieces of old sun deck railings (an awesome source of scrap square tube), and a beefy steel hinge about 8 feet long that just happened to be in our yard (that was a happy coincidence).
- Metal cut off saw
- Belt sander
You may notice in the pictures that I used quite a bit of galvanized steel, because it's what I had around. Now heed my warning, do not weld galvanized steel. It creates poisonous gasses when welded and even when grinding and cutting. Do as I say, not as I do.
- Angle Iron
- Flat stock
- Square tube
The capacity (length) of your brake will determine how big your angle iron needs to be. My brake is specifically for another project, so I only need it to be about 3 feet long, that just so happened to be about the length of my angle iron. If you want your brake to be longer you'll need to beef it up even more, but I wouldn't suggest making it much longer than this.
Step 2: Clean Up & Cut
Always wear your safety equipment kids. Eyes and ears, you know the deal.
The first step is to clean up all your metal. I used a belt sander to get the rust off the steel because it worked way faster than using a grinder. Use the cut off saw to cut everything to length. The angle iron and the flat stock will be your longest pieces. The flat stock will act as your die, so while you're cleaning it up and cutting it, put a radius on the edge that will do the bending; you don't want to bend around a square corner, you need a radius. The square tube will be about 3 or 4 inches shorter than the flat stock, this will be the stiffener. The hinge will be approximately the same length as the square tube. The lengths don't need to be exact, you just need space for bolts to attach the die to the one piece of angle iron. I also used the cut offs from my angle iron for outriggers on the base plate, these were about 12 inches long.
Step 3: Drilling
The drilling step is easy. All you need are a couple holes to clamp the die against the base piece. One hole in each end of the die will line up with one hole in each end of the base plate. Again the exact location of the holes isn't that important, what's key is that the edge of the die line up about 1/8" back from the edge of the angle iron. In order to adjust for material thickness I made the holes in the angle iron bigger, so that there is some room to play with the placement. In order to make it line up correctly, the best thing to do is clamp the pieces together where you want them and drill both pieces at the same time.
Step 4: Welding
The first thing I did was to stiffen the flat stock by welding the square tube onto one side of it. It doesn't need to be welded the whole length, just stitch weld it a hand full of times.
The second step is to weld some outriggers to the base plate. I didn't do this until after I was done, but it should be done before welding the hinge in place. I used the cut offs from my bending and base plates and just welded them onto the base plate at a right angle. This way I don't need to mount the break in a vise or anything.
Next is to weld the angle iron pieces to either side of the hinge. To line this up properly I stood the hinge on edge on the pin side, then put one side of the angle iron upside down to line up with the edge of the hinge. That sounds wordy but what you want is to line the angle iron up tangent to the hinge, I show it as best I can in the sketch and corresponding picture. The same applies for both pieces of angle iron. It's best to weld on both edges of each hinge leaf, on the free edge, and near the pin. Again a hand full of tack welds should do the job.
Finally, you need to weld a handle onto the bend plate, just put it somewhere in the middle. Make sure it is welded firmly as there can be a lot of torque on this one piece.
Step 5: (News Team) Assemble & Use
Now blow into the conch and the pieces will assemble...no? Well it's pretty easy regardless, just put some bolts in the holes that hold the die to the base and tighten it down on your sheet metal. That's it. When you tighten your die down, you want to hold it back from the edge of the angle iron by the thickness of the metal. I could go into bend allowances and radii and what not, but let's be honest, this is a rigged up shop brake, and you probably don't need to be that careful.
Step 6: Video
Here's a video of my first test bend.
Step 7: Review
After having used the break for it's intended purpose, I have determined that it was only a partial success. This break would work well enough for thinner material, but at the thickness I was bending, a 3 foot length is just too long of a piece for this design. The die was not strong enough for the bending forces required, and it would flex when bending. The break worked well for my small pieces, about 1 foot long, but I had to finish the 3 foot pieces in the vise with a hammer, unfortunate. I should also add a couple more handles with a cross bar between them, to even out the force along the bend plate.
II think I will try replace my original die with another heavy piece of angle iron and see how that works out. I am also going to try forgo the bolts and just use C-clamps. I will post again when I have finished the changes.