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I Forge Iron

Large Flat Rings


Buzzkill

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My wife wants me to make a decorative piece which will require a flat ring roughly 30 to 36 inches in diameter about 2 inches wide and 1/8 inch thick. Since it's for decoration it doesn't matter if the inner edge is thicker than the outer edge due to the bending.

I do not have access to any devices for rolling rings, so I'm wondering if any of you have good tips for accomplishing this. 

Any thoughts on bending the ring the easy way, welding it, and then heat and beat to accomplish making it the hard way vs. trying to bend it the hard way initially?

I can probably use a 55 gallon drum or a semi truck wheel to create some kind of jig if I go a little smaller, but I'm open to suggestions.

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That's easy cold work. Rig a couple movable helpers around your anvil to support the work and using medium light blows from a smooth faced hammer around 2 - 3 lbs max and work along one side. It WILL turn into a circle as you go round. Strike the strap on the flat, you're stretching the outside of the ring, NOT bending it. It's easier to tighten up the ring than relax it out so start easy and sneak up on it.

Space blows EVENLY unless you like lumpy out of round rings. 

Any bladesmith can tell you what happens forging a single face on a blade, this is just making it work FOR you. Hmmmm?

Frosty The Lucky.

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Just to make sure I understand you here...   You're saying to lay it flat on the anvil and just work one edge cold which will in turn create the natural tendency for the stock to bend inwards on the opposite edge?   You think I can get a complete circle that way without getting really thin on the outer edge?  I guess there's one good way to find out, but I'd rather not screw it up and waste the time if I can avoid it.   

Thanks for the nudge.  I knew that I'd end up with a thinner outer edge than inner edge, but I didn't consider doing that intentionally to create the ring.

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Yes, lay it flat on the anvil, you're stretching the outside of the circle. The stock is only 2" wide so the finished circle's outside circumference is only about 1.5" longer than the inside, a 30" dia. circle wants about 96" of stock and 36" wants about 113". Making the outside half 1/64" thinner will stretch the outside about 1.8" to make your circle and a bit.

Work from the center outwards, not just the edge you need to stretch enough to make enough force to make it bend. 

Try it on something, say 1/4" x 1" x 10" and play around with it. 

Frosty The Lucky.

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I'm just making sure I understand this

919282176_Screenshot_20190405-1601202.png.a6b9521bea1243b0fb9a1d6e2c238208.png

You lay the bar(black) down flat on the anvil and use med light blows on one side(blue), causing the bar to curve(green)? 

I'm going to have to try this one. I also saw JLPs video of a non welded ring that might work for your project, I was going to try it out as well.

 

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No, I don't think you understand Shabumi and your drawing is just confusing. This is a FLAT ring, NOT a hoop like going around a barrel or wagon tire.

Jennifer is forging a FLAT RING, it's a good example of a flat ring but the process is totally inappropriate for what Buzz wants to do.

Let's see if I can make this a little more clear for you. Draw parallel lines a 2" apart on your anvil. Visualize this being 1/8" x 2" strap stock laying flat on your anvil. Without lifting it strike blows one side of the center, that will make it thinner but wider that side of the centerline. By making the stock wider on one side of the centerline the steel will bend AWAY from the side struck. It won't want to stay flat but it can flattened and be trued up easily.

Does that make sense? If not, give it a try on some strap stock, strike one side of center and watch what happens.

Frosty The Lucky.

 

 

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I'd already gone to the shop and did a quick demo of the method for forging a flat ring I was talking about. The beginning stock is 1/8" x 3/4" and I spent maybe 5-6 minutes. Where the bend is sharper is where I struck closer to a full half way, the more shallow is where I struck mostly edge.

I could;t believe how out of practice I am, please disregard the evidence of hammer edge marks. :unsure: 

Frosty The Lucky.

 

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233726918_flatring01.thumb.JPG.dae8d32721126de8b419a6a3bcd44f9e.JPG

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Cut it from 1/8" sheet with a cutting torch, plasma torch, water-jet,  laser, ...

I've had several friends who had a neat doohicky that clamped onto the cutting torch shaft and had a point that would go into a center punched  dimple and cut a circle. I showed one friend a speaker magnet that had a keeper with a drilled and tapped hole that worked just as well and didn't mar the center disk if that was what was wanted his 1 rivet pots went to zero rivet pots!

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I had thought about something like that, but I don't have any sheet nearly that big and the only cutting tool I have access to for the job would be an OA torch.  I think between the cost of the sheet compared to flat stock and the inevitable cleanup needed after torch cutting there's probably a lot less cost and close to the same amount of time in Frosty's suggestion.

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I picked up a number of lab stand clamps from a dumpster years ago that I use with 1/4" or 5/16" rnd for a circle cutter. Center punch and use as long a length to make radius. After someone here mentioned using a speaker magnet, I found an old drive magnet with a hole in the center for the pivot. It clamps to a jig or chain saw even. Handy things those lab stand clamps. 

How to cut a ring wasn't the question though. ;)

Frosty The Lucky.

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id use my post vice, a scrolling wrench, a bending fork, and a twisting wrench.. Make the fork and wrench a bit over 2" wide. Also a few stands are a necessity. level your stands to the bottom of your fork so you can keep in plane. You should have no trouble edge bending 1/8"x2" with this setup.I would check for twist all the time and correct it as you go, or you will end up with a mess. Check for flat as you go as well. If you dont keep these two problems under control as you edge bend small sections, the error accumulates and you dont want that. Also, if you are not using a jig, draw about 1/4 or so of your inside radius on a table, floor, or what ever you have, and fit to this. 

So the process is

1: edge bend 6" and fit to pattern.

2: correct for flat(in plane)

3: correct for twist

4: recheck to pattern and correct fit, twist, and flat.

5: repeat

If you need pics of setup and tooling, let me know

 

 

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On 4/5/2019 at 7:42 PM, Shabumi said:

Yes that's makes it more clear. And I don't know why I thought it would bend towards the blows, as soon as you said it I had one of those DUH moments and slapped my head. Thank you for the clarification

You are not wrong in theory only in execution of method.. It will bend that way if not corrected and hit not to deform the metal along the center line..  Frosty only hit on one side or the bar thus expanding this edge only.. 

 

As an example you can try yourself..  

Take a section about  8" long mark it at 8" say  1/4" to 1/2" sq or round stock  (what ever you have handy) and take a full heat on that 6 or 8",.

 Place it at the edge of the anvil and start bending it down like forming a 90 bend hitting only at the edge of the anvil not the end of the bar... The end of the bar will in fact start to bend upwards..  An object at rest wants to stay at rest and then when you hit it that end (6 or 8" away) will want to stay at that position in mid air and if done well will be nearly where it was before you hit it.. 

What Frosty is saying is if there is adequate deformation or the material it will not bend upwards..  My Answer is it :::   This is true depending on how it's done..   The bar Frosty hit is in fact starting to bend upwards as well as curving from the deformation.. There are several different effects involved based on how the metal is moved.. 

But with that said if you take a round faced hammer and hit it only in 1 spot it to will start to bend upwards around the hammer strike..   But this is deformation  in a different way..  

I'll take some pictures later..  Forget the pictures.. 

I actually took some film while one of my buddies were here as he was getting ready to have a nail making lesson.. 

I demonstrate how the metal moves..   Also the bar on the anvil in the first part is in fact straight.. it has a slight twist but the footage with it against the straight edge was deleted and I didn't want to cut and paste it back in.. 

Shabumi you will find it interesting as it addresses exactly what you were asking.. Feel free to hit me up.. :)
 



 

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Thanks for all the responses.  There's several good ideas in there.

FWIW, I took a length of 1" wide by 1/8" thick stock and worked it cold using Frosty's suggestion and was able to get a complete circle about 24 inches in diameter.   It did take me a little over an hour of hammering to do it though.

The stock does want to warp in some weird directions, but I just let it go and then flipped it over for the next pass.  That corrected nearly all of the odd warping.

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You had me for a second there Jennifer and I had to go back and check to see if I'd left out having correct the warp to keep it flat. I didn't forget, WHEW!  

Forging a ring this way is easier with thicker stock, 1/4" x 2" is much easier but I've turned closed spirals in 1/4" x 1" strap for a "Viking" frying(?) gizmo as seen in the Mastermyr or one of the other viking finds. A friend of mine linked pics and we forged a couple up one afternoon. 

Forging hot is easier though handling 100" long hot would be problematical. 

And there's BUZZ! 24" dia. is a big test piece but an hour isn't bad time, it's awkward to handle. Give other methods a try though, see what you like best. Just because it isn't right for today's project doesn't mean it won't be perfect for another you know. ;) 

Frosty The Lucky.

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I guess frosty was right, my drawing was confusing. Funny, it made perfect sense to me when I drew it. But hearing how others perceive it, I can see how it would confuse. I hadn't meant that the bar would bend up, instead I thought it would bend towards the blows on the edge, along the flat of the bar. I did, however, have a brain lapse and forgot the basic principle that metal moves away from the hammer, not towards it. Too busy looking at the forest, I forgot to look at the trees, or the ground it's growing in.

A quick follow up question about Frosty's method. Should you normalize periodically to relieve stresses from working the metal cold?

JLP, that was interesting to watch. I didn't realize that steel would move like that. Another thing to try out when I can get a little more free time. My first thought when I saw this was "Wow, what an easy way to make some bolt tongs. 3 hits and it's mostly done."

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22 hours ago, Shabumi said:

A quick follow up question about Frosty's method. Should you normalize periodically to relieve stresses from working the metal cold?

I never applied any heat to the stock when I made the roughly 24" circle that way.  I would say that there was some minor work hardening that happened, but not enough to justify the hassle of trying to evenly heat and cool that rather unwieldy stock part way through.  If you don't get even results then you'll probably get a wobbly ring.   It was a lot of hammering to do it that way, but for a one-off I think it's probably better than most other options.   If you had to make a dozen rings you'd probably want to build some kind of bending jig and/or work hot, but I figured it would take me much longer to build a suitable tool for the job than it would to hammer one ring out.  I stand by that decision.

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Interesting that other methods were mentioned, but that is our way.

Edge bending is best done two ways.

One way involves a $12,000. machine and $1000 in special dies.

The other way is hammering the outside edge. 

As Frosty mentioned, 1/4 is way easier, I wouldn't bother using 1/8", too much effort. 

Whenever I have to make curved hinges I always hammer the edge. Twisting, curling and warping are dealt with, corrected on the anvil while hammering in the curve; once you get practice at it, it should come off the anvil flat.

It is remarkably easy to correct and do an accurate job.

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