A major commission for me, a gril

[yves]

Biggundoctor,

Here is the jig I used.

I put the end of the 1/8"x3/8" flat in the stopper in the first heat and bend as far as I could.

In the second heat I moved the end of the bar to the side and bend (with a third heat at times) under the end of the flat. Then I cut the ring with a chisel.

 

[anvil]

4 hours ago, Marc1 said:

As for shaping rings on a cone mandrel how do you get them all the same size?

Im pretty sure on the post, i screwed up.  And that happens as you said on my pc as well. its saved me a number of times.

Sizing rings on a cone mandrel.

I figure the length needed to make my ring, then cut these on my shear or bandsaw to length. I do a quick and small scarf on each end. Then either by eye over the edge of the anvil, or most likely with a set of bending forks and scrolling wrench i turn them into a circle. half inch and smaller i do cold. 5/8" is a tossup for turning them hot or cold. i get them pretty close to a circle by eye. 

Then, depending on the job, a quick forge weld, which works well in the above grill. The weld is hidden from view. With a small scarf, you should be just a bit smaller than your final diameter with one heat, and this will be a bit thicker than your parent stock. Im not sure, but if you do a quick tack with welder or gas, it might break when shaped. This prolly depends on experience.

a good cone mandrel has a tong groove which is really a bonus. Now lay out your ring diameter around the mandrel with chalk, or marker of choice. get a light heat, say a red or light orange on your ring(s). slide it on the mandrel and as you perfect your round with light hammer blows, it will slide down to your mark. lightly forge the f/w to proper cross section and you should be at the needed diameter and right on your mark.

I dont use gas but this is a perfect place for a gas forge. Toss in a bunch, get them to temp, and size as above. I do these in my coal forge and can maintain about 4 at a constant temp basically the same way a hot shoer manages 4 shoes. I have yet been able to outwork this procedure. 

Of course when doing a lot, i do this as what i call a limited production run. cut all, scarf one end on all, then the other, turn them, weld them, fit them to the mandrel.

If they get chamfer edges, I usually do that on long lengths before cutting them to the needed circumference.

An added note: Im pretty fanatical about correcting edge bend and twist. Twist isnt an issue with round, but is an always thing with square stock. I check this at the end of every step above. when you work square on the mandrel, the bottom edge is the place for hammerwork. keep an eye on it and you can correct any twist at this step. This is critical when doing final assembly or your collars will be a bi**h.