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Making a simple sheet metal folder

by

Robin Martin

There are numerous times during the construction of a Pembleton where you need to put a fold into the aluminium used to create the body. There are various ways of doing it using blocks of timber bits on angle iron etc but I wasn't happy with making so many bends that way so I thought a "proper" sheet metal folder was the way to go. There are plenty of small ones available sub £100 but nothing that would do the width of fold needed for the Pembleton.

I browsed the web for any suitable DIY designs - and there are plenty. But some of them require machining facilities and virtually all of them require welding - neither of which I have the equipment for, or are capable of doing (or wanted to pay anyone else to do).

So, - in the end I came up with my own simple design using some large sections of angle iron and the most robust hinges I could find (from Screwfix).

It produces great folds OK either mounted in a vice or on my workmate. I purposely designed it to produce 'soft' folds without a sharp crease as I recon these will be less prone to fatigue cracking in later years. The only problem it has is that, despite using large sections of angle iron, the bend is a little less well defined in the middle due to flexing. Nothing serious - just not quite perfect.

I used the following materials:

Construction notes

The trick is to mount the hinge in such a way that the edges of the two pieces of angle forming the fold rotate relative to one another without any other movement (which would cause them to move relative to the material being bent) It order to do this I cut a small notch in the angle iron so that the hinge pin was at this centre of rotation. Can't explain it any better that that - look at the pictures to see what I mean!

I chose to mount the angle iron that is the clamp with one edge, rather that the angle, to form the fold. This produces a softer bend. The position that this angle iron is at is crucial to getting a neat bend so be careful with this.

Some of the angle iron available is really scanky. I had to clean mine up carefully with a flap wheel in an angle grinder to get the mill scale off.

And finally - if anyone comes up with any improvements please let me know! Particularly the problem of curing the flex in the middle.


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