Five Minute Sheet Metal Brake

[echris 1,425]

While making a mulching cover for a 42SD the other day, I needed to make a 90 degree bend in a 1/16" anodized aluminum sheet.

I don't have a brake, so I hunted around the shop for something to do the job.
For years, I've just used my vice and hammers/mallets for smaller jobs.

 

In this case, it's brittle aluminum and around 18" long and I wanted a nice even bend.

I found these pieces of aluminum chassis sides from some old electronic equipment, with nice gussets on the back and a hefty right angle on top.

I slid a pair of them into the vice, and clamped the workpiece in between

 

and then added two c-clamps underneath to keep it nice and tight together.

 

I wanted to get the bend as even as possible, so using a 24" bar clamp, I clamped it to the top side of the workpiece with a couple of pieces of wood and used the bar clamp as a handle to bend the aluminum around 45 degrees or so, moving the "inside of the bend" block of wood upwards a few times during bending to gain more clearance.

 

Then using a rubber mallet, I flattened the bend gradually from either end towards the middle.

This is the result. 

 

I REMEMBERED TO DRILL THE HOLES FIRST! Shocking, I know! hahahaha
 

 

But this worked great. I'm going to have to assign a tool number to these parts with a Sharpie and stick them in a box. 

 

[ebinmaine 67,596]

Niiiiiiice

[threepiece 6]

It irks me when someone uses the excuse of not having a metal brake. I make long bend like this regularly while my 48”x16ga.metal brake sets unused in a remote corner of my shop. I use a technique somewhat similar to the one shown here however I use hammer blows rather than lever force to do the bend.

 

I clamp the sheet metal between a fabricating table and a flat bar in a similar way shown in the picture above. I leave the shortest leg of the bend hanging out over the edge of the table. I then use a block of hardwood (Corking Tool) and hammer to move the metal. My fabricating table is an 1800 lb. tooling plate I bought from the scrap yard. This large mass helps to transmit the energy from hammer blows into the workpiece much like a large anvil in a blacksmiths shop.

 

This technique requires some experimentation and skill. Different size hammers and different width corking tool will give different results. With a bit of practice bends can easily be made that are as good as those made with a brake.

 

Additional advantage is the variety of bend radii that can be made. By rounding over one corner of a flat bar and using it under the sheet metal, a larger radius bend can be made than that of a sharp corner. Even larger radii can be made by tack welding a piece of round bar to the edge of a flat bar. For example: a 1” round bar welded to a 1” flat bar. With this, a bend with a bend radius of 1/2” can be made. 
 

For occasional bending I found a heavy steel table much more practical in the shop. They are more versatile than a brake and won’t take up more precious space than a table that one would already have.