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Bending on the edge


Grundsau

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When making trivets I've been heating up a section of flat stock and bending it over the anvil horn.
Once the ring is close to where I want it, I true it up on a cone mandrel and forge weld it.
I can get the ring pretty close just on the horn.
I'm working mostly with 3/16" x3/4" and 1" flat stock.
Is there a quicker way to bend a trivet ring on edge?

I have a P5 flypress and can make a ring roller for it.
Wasn't sure if that would be enough force to do it without putting gouges on the inside.
Maybe while it's heated would be better.

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Bending on edge is always more difficult than on the flat, a fly press or ring former will need to have vertical supports to stop the twist tendency.

I would go for making a jig the internal diameter required, and a movable stop to suit each size of bar width, mounted to a flat plate, (the ring for the jig only needs to be slightly thicker than your flat stock)

Then heat the stock and pull it around the jig, you could use bending forks, or make a crank handle with a pin/roller on that fits into a central location and just pull the ring to the jig, hot for a neat fit or you may get away with doing it cold, but it will spring somewhat.

Cut your metal slightly longer before starting, and you are ready to forgeweld the ring

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Screwpress is nice for flattening a ring after it has been pulled around a jig. I do it hot.

Of course for small rings you can bend them pretty roughly and then true them up on the cone mandrel/fly press after you weld the overlap.

Some of it depends on how much hammer work you want to show. I rather like having the entire outer edge of the ring to be nicely hammered.

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Those are some good ideas and have me thinking.
As long as there is lateral support on a pipe type jig maybe a pair of tongs could be used when hot bending.

How about this?
If I can find a pipe in the correct OD, I could plasma cut two giant flat washers from heavy gauge sheet metal for the lateral support.
They would slip over the pipe and be welded into place with a 1/4" gap.
Both supports would also be tall enough to keep the trivet from wanting to lay over.
Some kind of stop would get welded onto the pipe at the beginning of the bend.

The end that the tongs are holding could easily be reheated and hammered into position on the horn if need be.

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Those are some good ideas and have me thinking.
As long as there is lateral support on a pipe type jig maybe a pair of tongs could be used when hot bending.
How about this?
If I can find a pipe in the correct OD, I could plasma cut two giant flat washers from heavy gauge sheet metal for the lateral support.
They would slip over the pipe and be welded into place with a 1/4" gap.
Both supports would also be tall enough to keep the trivet from wanting to lay over.
Some kind of stop would get welded onto the pipe at the beginning of the bend.
The end that the tongs are holding could easily be reheated and hammered into position on the horn if need be.


haha! Who are you trying to kid?

I spotted your deliberate error, karnt fule me, I bin to kolij! ***

I have made similar to John B's suggestions with a plate profile and centrally pivoting lever with a roller follower which can be stepped or grooved to hold the edge in plane. Depending on the number you have to make a ring of flat bent the easy way can be welded to a base plate and then the workpiece can be nipped around to it with scroll wrenches.

****how you going to take it off your jig after bending? One washer needs to be demountable!
Edited to add that the inside of course thickens up so even with a demountable washer you would still jam.
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First thing I thought too; though pretty easy to make the top washer demountable.

If you make your jig base fairly thick you can hammer the ring flat as you go around it and it tries to rise.

However bending it on a cylinder rather than a come helps keep things straighter anyway.

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Oops, did I say I was going to weld both ends? LOL
Thanks for the help.


The serious side of my response is that it is the outside edge which moves out of plane, the inside edge stays where you put it against the jig, Thomas' point about the advantage of a parallel or cylindrical former rather then a cone pertains here. Which is why concentrating on controlling the outside edge in a groove in the follower wheel or by holding it down against the base plate with a stepped wheel is favourite. The outside edge is of course getting thinner so your guide slot / step can be a good fit to your 1/4 and still not jam.
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Big-D, I tried that idea and the outside edge doesn't want to stay in alignment.
I was applying so much force on the 3/16" x 1" material that the cone wanted to move around.
We have specific trivet sizes so a fixed jig for each will speed things up.

Does anyone have a drawing or photo of what the follower wheel with groove should look like?
Or how to make it and then remove it to get the ring off the jig.
Still trying to wrap my head around that.

This week I am getting last minute items made for a folk art show this saturday.
Next week I'm going to a plumbers shop to look for some pipe.
Would like to get this jig put together soon.

Thomas, what thickness should the washer base be if I want to hammer on it?
3/16" or 1/4" plate cut to size is available for one end of the jig.

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"As heavy as possible" it's being used as an anvil after all...

We were making bent the hard way rings last Saturday and I was showing a new fellow a lot of different ways to do it: with long pieces using a jig, with short pieces using a "ski slope" hardy tool, bending around the horn, sticking in the hardy hole and bending. Almost all of them require flattening on a regular basis.

It really is *much* easier to not worry about perfect circularity until *after* you do the forge weld and then heat as much of the ring as you can at one time and true on a mandrel.

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It really is *much* easier to not worry about perfect circularity until *after* you do the forge weld and then heat as much of the ring as you can at one time and true on a mandrel.


I agree with that absolutely, especially if you can get the whole ring evenly hot so you don't stress the weld.

I had forgotten you were going to fire weld the ring...the jig, lever and roller systems are more oriented toward fabricating work I suppose.

I will post some images of the variations of wrenches and wheel follower systems kicking around in the forge in a few days, they might be useful for you down the line.
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I have made large piles of horseshoes and alot of them had forge welded ends. though not in perfect circes, wot you are doing is really similiar. And all of them were turned over the anvil horn. When youdo alot they get real easy to shape. After awhile you can precut the stock. trun and stack them up when finished..remarkable how they will be almost the same size when done. i suggest cutting stock for a couple of dozen and forge them consecutive. Move this from your left brain into the right brain style of work. make it second nature like starting a vehicle with keys. I would forge to shape and prep ends for weld the go back and weld ends as second step.

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The ski slope hardy tool was made from a piece of cutting scrap about 1.5" thick it had one flat side and then the top was a "hill" with two different slopes, one sharper than the other.

To use you stick the stem in the hardy hole and then heat your steel and place it on the anvil face and the top of the tool and use the hammer to hit down into the gap between the workpiece, the anvil face and the tool.

Handy to make curves on as your holding hand gets no hammer shock as it's a three point system. The two different slopes allow you to make differing radii bends.

I saw one being demo'd years ago and finally made one when the right piece of scrap came along.

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Those photos would be great.
I usually scarf the ends for welding before roughing out the ring and then it gets welded.
Sometimes I weld after shaping on the cone or before. Depends on how good of a job I did.

On my swage block, one end has a concave curve which I've used for half-round utensil racks.
It's shallow but it might work.

Rich, I often make multiple pieces when forging
But only two or three trivets get made at a time because that's about the maximum that fits in the gas forge and still allow me to be efficient.
This jig is supposed to speed things up so it doesn't take so long for each piece.

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Take a piece of pipe the same OD and the ID of your trivets ( assuming the trivets might be from 3/16 x 3/4 stock). The pipe is about 3" long and welded to a piece of angle iron ( to clamp in the vise). The pipe can be on top of the jaws or on the side, your choice. Heat the stock and wrap it on the pipe using pliers/tongs/channellocks/vise grips etc to get it started and hold when starting again. Wrap and forge flat (er) on the anvil. Figure a starting length and write that down. Wrap 3 times ( in that you said you do this work in 3's ) and have an overlap. Cut with a hacksaw. You now have 3 identical rings the hard way. They can now individually be taken to the far side on the heel area. Bend the ring under the heel and forge the scarf on the near side with the heel of your hammer ( somehow this is hard to type and get the message across ). repeat the other side and you now have enough for the weld to take place. Your ring should remain intact but of course will need flattened after the weld.

I like tooling for repeat business or production work. Once you figure your length, you should be able to make the rings several at a time but the stock needs to be bloody hot to bend it the hard way. Once the tooling heats it helps too.

EDIT: In reality, I just cut the rings and gas weld them together, heat and forge the weld and lay the feet out for forging. This process makes for fairly quick finished goods and I make no claim of " traditional " weld. Someone wants it that way i do it.

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As a former farrier, I side with Rich Hale's response. You can use your Pi x mean-diameter formula to get the circumference (length). Upset and scarf with scarf faces on opposite sides before bending. Realize that the metal will upset a bit on the inside of the bend and draw on the outside of the bend. This shouldn't be a problem for a trivet, but might be a consideration, if the ring is for another purpose.

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  • 5 weeks later...

When making trivets I form the rings and scarfs in the gasser first.
The next step is moving to coal for the forge weld.

Someone recently pointed me to a hossfeld bender with an edge bend die.
Those dies are near the bottom of this page: http://www.hossfeldbender.com/tooling/bar-angle-iron.php

I also have the need for circles and arcs for pot racks and angles in flat and round stock so this may be a good choice.
Now I'm on the lookout for a used hossfeld.

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  • 2 weeks later...

Got to see a hossfeld this morning and that is one serious piece of kit.
So far all of the used ones online have been going for close to what new sells for.
Batavia Machinery has them on sale till the end of the month. http://www.bataviamachinery.net/hossfeld.htm
May end up with one from them if something else doesn't show up.

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