How Would You Forge This?

[billyO]

Billo0, If I had remembered to mention the diameter of the ring, you may have realized that that would require heating a 56" long bar evenly. I could see trying to heat 24" evenly, but not 56.

 OK, fair enough, but a smith with MUCH more experience than me once said, "Cold is the most even heat you can get."  With a piece that long, being barely over 1/4" thick, and only doing 1/4 twist, I'd try twisting cold....

[JME1149]

I'm going to throw a slightly different view on this. The original picture showed the outside diameter being aligned as if the twisted ring was formed inside a cup. If you would wrap it around a mandrel, the insides would be aligned and the outside would have the step at the ends. Of course, it could be wrapped around a mandrel and then tweaked to match-up whichever edge you want. Looks to be challenging any way you go at it.

[arftist]

I used to twist 1/2 x 1/2 cold all the time, 3-4 turns in 24". 1/4 turn in 56 " cold is pretty doable. 

 

As to the bending, lay out a circle on your table if you can't find a form and bend it hot, one inch at a time, If you really need a form to bend against, you really only need a small segment of a 9" radius which you could cut out of plate or bend out of flat stock and weld to a piece of angle iron. 

[WayneCoeArtistBlacksmith]

I have done some forging a transition and I think it is what is needed here.

First, isn't the stock the same dimension on both ends but on a 90 degree different plane? 

So take the piece of desired dimension stock and twist it.  You will make the twist as long as desired.

Then forge out the twist.

There was an example of this early in the either the Hammer's Blow or in George Dixon's Traditional Metalsmith.

You also see this done when tongs are made from flat stock and the jaw area twisted to make the flat jaws, then the twist is forged out so that you can not see that the stock was twisted.

[doc]

Unless I'm missing something ?? Your examples seem to be a piece of square or round stock forged with two opposing tapers 90* apart. There is no twist. 

[dognose]

As I said in the original post, the stock is rectangular, 5/16 x 1 1/2". There is no change in the dimension of the stock throughout the entire length of the finished piece. you may be having a hard time envisioning the twist because it is only a 1/4 twist over the entire radius. As you can see in the pic, on the left, the bar starts outs bending the easy way then gradually transitions to bending the hard way by the time it reaches the end. Not sure if I could do any better describing it? At no point is there a square or round in the entire piece.

[Jim Coke]

Greetings Dog,

 

Now that I have reviewed your situation I have a better answer..  It took a while to jar the old boys memory..  You will find just forming a hard way bend on 5/16 x 1 1/2 stock in itself is very hard to do18 inches.  I have done this on an Eagle rolling machine and found that the stock thins on the outside diameter and thickens on the inside.  There is an answer.  You could cut a circle from plate to start adding an inch or so. Split and drill holes in the matching ends and wire the ends together to keep in round for twisting..  I would accomplish the twist by clamping it to a heavy table with a small part overhanging the edge and twist in small increments cold with a big wrench.  When finished trim the ends at the holes..  That's what I got.. I hope this helps...

 

Forge on and make beautiful things

Jim

[anvil]

lets see if I understand your concept:

1: 5/16" x 1-1/2" x~ 56.5" . no crossectional changes.

2: even 90` full length twist.

3: turn to fit 18" id circle.

question: where the ends meet, where does the vertical (1-1/2) meet the horizontal? inside or outside.


1: cut to length and perhaps do a cool transitional champher.

2: tools- forge, anvil, post vice, twisting wrench, scrolling forks, helper stands as needed,torch, ladle for water.

take a nice 8" -12" comfortable yellow heat. clamp in post vice and twist w/ wrench. use torch to add heat where needed or use water to cool where needed. the purpose is to maintain a descending even heat whilst twisting where needed to achieve long even twist.

2od heat overlaps first for a comfortable working heat. repeat the above.

the better your eye, the quicker and cleaner this will take and look :)

3: for my question above i'd u§e the same tools, but different setup.

draw in chalk an 18" dia circle on your table.

make a 6" or so pattern w/ handle to match a section of your chalk drawing out of 1/4" square

helper stands as needed

put 5/16" scroll fork in post vice and 5/16" scroll wrench in the approate hand

turn scroll hot or cold, as your pleasure demands. match to pattern. overlap sections if done hot. check and double check against drawing on table. tweak as needed 'til done.

duplicate 500 times. ;)

all ya gots to do is heat it and beat it.

[anvil]

a note to the above, when turning the scroll/circle, the twist is so gentle that those forks ought to work. when scrolling- there is another force added- a twist so as to maintain the constant twist in the stock.

pretty cool

have fun!

[knots]

I have been thinking abut this and have an approach that I think I would take a look at / give a try.

 

The solution might well be -  To be able to picture what a completed piece would look like if un-rolled .  Then forge the flat unrolled blank to that shape before rolling into it's final form.   

 

What you know is the the un-formed end would need no forging to be bent into the chosen radius since the start is vertical to the plane of rest.  You also know that the end of the work piece that rests flat on the plane of rest is formed to the finished diameter of the piece.  In your case 18".    You should also be able to deduce that the curve between the two ends will be a uniformly graduation from straight to 18" in diameter.  

 

I think I would do a mock up using a smaller lighter section to test forge , roll up, re-straighten and re-forge, and re-roll until I got the idea.  You might even use cardboard models to refine the shape.  Then work on the finished piece. 

 

Just thinking out loud.

[RogueRugger]

Without going in geek speak with things like half twisted cylinders and ouroboros, and admitting I'm the newbest of newbs here, here's my take. First, there's a material energy thing going on that will make radii smaller than a certain amount very tough (but not impossible) to do smoothly around a mandrel, especially if you do it cold. You can see this by cutting out a strip of paper and trying it.

As I think someone along the way hinted at, I'd do the 90 twist on the same length, same dimensional material. This will get you a template of sorts that captures the change in rotational angle evenly distributed over the length of the strip. You know a few of the angles along the length: 45 at 1/2 length, 22.5 @1/4, 67.5@ 3/4.

Then, as someone else suggested, I'd use this as a guide for the slow process of heat/bending fork/heat/etc. As with an Archimdean or geometric spiral, I suspect you will be able to tell when it doesn't look quite right, but by "rolling" the straight guide along the outside edge as you bend, it will keep you honest.

FYI- I think there was a candle holder at the ABANA 2012 show that had something similar. I could be mis-remembering.

[anvil]

I have made these before, with an added dimension. I did forget a few details. rogue runner reminded me.

so here's a bit more.

divide the stock, when flat, into quarters. center punch or light scribe. these are points of reference.

add to tools a set of bending forks for 1-1/2". angle finder.

angles are 22.5,45,67.5,90

edge bend 1st quarter using larger forks and fit to pattern, then twist. use angle finder to check for 22.5 at first reference point.
the rest follows same procedure as my first post and should fall into place and shouldn't need any more edge bend.

its been a while so w/o doing this to refresh my procedure, this should get it done.

[SJS]

If you have a gasser with open end ports, you flip it on end and run the stock up and down through the gasser to get an even heat over the entire length. Did it with a few swords no big deal.  Id start the bend the hard way across the 1.5" and work toward the easy way.  Welding up a full form to work against, and a torch would make it easier, but you could do it free hand over the horn and match to chalk line and tweak the axil twist...