DIY Make A Sheet Metal Bender: Frugal Workshop

We are in the middle of our house renovation at the moment. Our house is over one hundred years old and pretty much everything needs some amount of our attention in order to function. The walls all need plastering or frame work replaced. Stumping had to be done. Cladding needs replacing. Wiring … the list goes on. One of the jobs to do is the flashing around our chimney, that leaks more than my eyes during an Ed Sheeran song. So I made a sheet metal bender out of scrap material to make our chimney water proof again. And this article explains how I did it.

Left over scrap steel used for this project
Left over scrap steel used for this project.

Two things I like: making things from scrap steel, and making something with mechanical parts (I hope to one day build a car). Even a hinged joint is a mechanical part. Two pieces of material moving together to create an action, like a hinge, has to be one of the simplest mechanical joints, and a very useful one at that.

For a long time I wanted a sheet metal bender, otherwise called a box-and-pan brake, a finger brake or even just a metal brake, depending on its functions. When I was at secondary school, in the plumbing class, they had a couple of large floor standing models that were fully adjustable. The type you could fold a box with. Plumbers use them to make air conditioning ducting. However, these things cost a fortune, and if I’m honest, would never be used to their full potential in my shed.

A new steel metal bender this can cost thousands of dollars
A new steel metal bender like this can cost hundreds of dollars.

Regardless, I still wanted one. So I set about making a small bench mounted version using scrap steel I had laying about.

I knew what I needed it to do. I needed it to be able to create a sharp bend in sheet metal. I needed it to be accurate. And I needed it to be strong.

Any flex in this thing would result in it not meeting my first two requirements, so heavy steel was chosen and plenty of time to properly think out my design was utilised.

There are three main components to this:

  • The bed. This is the part that will mount to the bench, or if I want to fit legs, they will mount to this. It needs to be pretty tough.
  • The hold down clamp. This holds the sheet metal in place on the bed, and needs to be heavy enough to have holding power, and rigid so as not to move or flex under load.
  • The folding blade. This also needs to be rigid, straight, and mounted in the right position in order to make accurate folds. A long handle for leverage attached to this makes bending metal a lot easier.

Choosing the Right Materials

First I needed to decide on the length. Given that I had a couple of one metre lengths of heavy steel at hand, that decision was easily made. I used 5 mm thick U shaped beam as both the bed and the folding blade, and 40 mm x 40 mm angle that’s also 5 mm thick as the hold down clamp. This should give me the rigidity I need.

I also have some 10 mm bolts, a short length of all thread, a piece of pipe and some nuts for the handle, and I made hinges from spare locating pins I had, and some small pieces of scrap.

Attaching the Hold Down Clamp to the Bed

The bed is what it all attaches to so I mounted the hold down clamp to the bed using two bolts, one at each end, and welded the nuts for these to the underside of the bed. The clamp needs a small amount of movement back and forth to allow for adjustment of the material thickness I am folding. It only needs to be a small amount, so I made the holes in the clamp a little larger than the bolts I am using.

The bed with  the hold down clamp away from the edge
The bed with the hold down clamp away from the edge.

The Folding Action

The front edge of the bed and the leading edge of the folding blade is where the action happens so I needed to be somewhat accurate here.

The locating pins I am using need to be positioned in such a way that the two edges of the bed and the blade is where the centre of the pin (one at either end) needs to be to create the folding action. So I notched out each part so the pin sat in the correct spot. Then I welded the pins to the folding blade only.

I lined up the centre of the pin with the corner of the folding blade before welding in place
I lined up the centre of the pin with the corner of the folding blade before welding in place.

Using a piece of pretty thick metal, I drilled a hole the size of the pin, sliding it on, checking the blade and bed are still in the correct position, and then welded it to the bed. Then I repeated this on the other side.

This piece welds to the bed, completing the hinge joint. I even have a small hole in the top for oiling. Pretty fancy
This piece welds to the bed, completing the hinge joint. I even have a small hole in the top for oiling. Pretty fancy.

This has now created the hinged joint, and the folding action for my newly built piece of hardware.

A Handle and Feet

The handle was made using the allthread which I screwed the nuts to, and with a little persuasion they slid right into the piece of pipe. I made it long enough to make the lifting action easy (the longer the handle, the easier the movement), and removable so it’s not in the way when not in use.

The longer the handle, the easier the lifting action
The longer the handle, the easier the lifting action.

This thing really needs to be bolted down so it doesn’t move while trying to use it, so with left over bits I made super simple feet with holes in them and welded them to the bed at each end.

Note my piece of practice folding metal on the bench
Note my piece of practice folding on the bench.

The End Result

This thing works great.

Great enough that was able to fold up the new flashing for our leaking chimney.

The folds aren’t quite as sharp as I was aiming for, which shows that I rushed the set up and assembly a little, but otherwise I am pretty stoked with what I was able to achieve.

First piece of metal flashing installed. So pleased with the outcome
First piece of metal flashing installed. So pleased with the outcome.

This thing will be well used in our shed. And made from scrap. It’s amazing what you can create from nothing. To buy a similar bench mounted type is easily upwards of $200 plus delivery and doesn’t come with the satisfaction of knowing you did it yourself.

And I’m so glad I did.

Just remember to have a crack. What’s the worst that can happen?

Mr Hack

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