Hammer forming a Splash Apron

[enjenjo]

Hammer forming can be used for many shapes from simple to
complicated. This is a simple one. If you want some
advanced information on hammer forming, there is a book by
Ron Fornier that has some very good information on doing
it with many pictures.

The first thing we need is a blank. This would be the
material we are making the part from. In this case it is
18 ga. cold rolled steel. You can use most any metal, the
softer the better. But even very hard materials can be
hammer formed using ceramic forms, and heat. I laid out
the blank using a stock apron, and the new bumper, and
a few measurements on the truck. After layout, I marked
another line 5/8" larger than the form, and cut the blank
on that line.

[enjenjo]

Now to the form. Again, this is a simple part, just flat
with a formed edge. And the plan is for only one part,
so it does not have to be that durable. So I used a
piece of Maple die form plywood I had on hand. I have
worked with this in the past, and knew it would serve
for one part. You could use HDF board or a similar
material too. If the form has to be durable, you can use
metal. Harry Miller's race cars had frame rails hammered
over a cast iron form back in the 20s.For a form with a
lot of shape, you can laminate wood, or use bondo, or
any other relatively hard material. Just make sure it's
strong enough to pound on.

Depending on the edge shape you want, and the form
material used, you might have to radius the top edge of
the form. Having worked with this material before, I
knew that if I left it square, it would give me about a
1/8" radius on the edge, which was what I was aiming for.

So, I laid out the form, cut it close with a band saw,
and sanded with a disc sander, and belt sander to the
final shape.

[enjenjo]

Now we have to join the blank, and the form. I laid the blank upside down so I could see the layout marks, and clamped the two together.  Normally, at this point, I would make a duplicate form about 1/2" smaller than the original form to clamp the blank. But since this was a simple shape, I just made a duplicate of the ends, and clamped scraps between the ends to hold the blank in place. You can not have too many clamps. The more clamps, the better the job. On a small part, or one that has to be duplicated, you can drill the form and blank, and use pins or bolts to keep parts from moving.

[enjenjo]

Now we start the forming. I first use a dead blow mallet, as it leaves no hammer marks. I hammer it in steps, bending a little at a time, until it's nearly done. At that point, you will see ripples that form on the part you bent down, as the metal needs to shrink at the edge. At this point, I use a body hammer to tap along the bottom edge against the form. This will shrink the edge, making it fit tightly against the form.

[enjenjo]

Now we come to the areas that have a lot of shape. As the edge is bent down, it will form some big ripples. Since the form is not that hard, it would be difficult to shrink them against the form.  So I set a thin spoon behind the ripple, and shrunk against that.  When there was not enough room for the spoon, I shrunk against a piece of sheet metal, until it was flat enough to shrink against the form.

[enjenjo]

That about does it.  I removed the form from the part. I found a couple spots that needed a little hammer and dolley work, it only took a bit of touch up. I still need to trim the edge so it's even all the way around. I am also planning on raising a panel in the middle with my bead roller, but I set it on the truck and it fits like it was made for it.

[Digger]

Nice work Frank

[zzebby]

You make it look easy.  Show us the next step, the bead rolling.

[OldSub]

Nice work.  Thanks for showing us how its done!

[chimp koose]

thanks for the lesson

[57larry]

very nice. I'd like to see some bead rolling too

[UGLY OLDS]

Good Job Boss.... );b(     You make it look SOOOOOOOOOO Easy ....

 How do you shrink with the spoon??   Is that like working "off dolly"

 Bead rolling coming up next??

Thanks for the lesson .....




Bob............

[taxpyer]

Very good, Thanks for the time taken to show us.

[enjenjo]

How do you shrink with the spoon?? Is that like working "off dolly"

You use the spoon to tuck shrink the edge.

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[Okiedokie]

Great thread, thanks for posting it.