Making a Radius Bending Fixture for Sheetmetal

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I often need to make radiused bends on sheetmetal for tanks and other projects,

so I made a simple device that attaches to the edge of my workbench.

It works like the apron of a brake.

The apron is made from angle iron with round pins welded on each end.

The pivot blocks are a simple fabrication, which bolt to the edge of my bench,

with holes that engage pins on the end of the apron.

To make a radiused bend, a piece of round stock is used as the die.

The sheet metal is placed under the radius die, and the die is clamped to the table.

You certainly could attach a handle to the apron, but I simply use an adjustable wrench.

As you can see, simply clamping round stock to the bench doesn't work very well,

since the pressure made by the bend may cause the die to roll or slide.

An easy solution is to tack weld a piece of square stock to the backside of your radius die.

This allows you to clamp the die securely, and prevents it from rolling.

As you can see, I've made a lot of different sized radius dies,

and it's easy to make more as the need arises.

Another great feature to have is a stop block,

so you can release the clamp on the radius die, hinge it up,

and then reset the die in exactly the same spot.

This stop is made from a small block of wood.

So let's go through the process of making a couple of bends.

I often keep one end of the radius die clamped to the bench,

and pivot up the other end with a small wedge if needed.

Then, the metal to be bent is slipped underneath the radius die,

and the loose end of the die is clamped down tight.

The bend is made by rotating the apron. In this case I'm going to 90 degrees,

but your bends can be any angle you want.

Once the first bend is finished, the clamp is removed,

and the part can be repositioned for another bend.

As you can see, this is a great way to make bends of any radius you like,

on metal as wide as your fixture,

and this setup also allows you to make bends closer together

than you could with the standard leaf brake.

Now let's go through the process of making an actual tank.

I've already made the layout on a piece of flat metal, and decided on the radius I want for the bends.

The first step is to use a Rounding-Over die on the two long ends of the tank,

so the weld will be in a corner, and the radius of the welded corner will

match the radius of the bent corners.

The first bend line is aligned with the edge of the apron,

and the radius die is clamped into place.

The first bend is made.

Now, the die is unclamped, and the part is positioned for the second bend.

The last bend is made in the same way.

This would have worked better if I'd made each bend a little tighter,

but light pressure will hold the parts together when the joint is welded.

To finish a tank, the end piece is made from flat metal,

and the edges are curled with the Rounding Over die.

Next, the tank ends are rounded, and the ends can be welded into place.

A simple radius bending fixture like this can make a lot of other components as well,

such as hoods for cars,

splash aprons,

and pretty much any component that needs a radius bend.

That's it for today. I hope you'll check out my other YouTube videos.

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