Forming Ridges

[Scott NC]

  I'd like to make a forged sculpture of an ammonite, a "living" one, not a fossil.  Not very big, 1" bar stock.  I think I have all the details worked out, but am having trouble figuring out how to do the ridges on the shell, as they get progressively smaller.  I'd post a picture but it's copywrited, I'm sure, so I'll put in a link to exactly what I want it to look like.  I thought of hammering and chisels, edge of the anvil, etc.... but I want both sides identical.  Any ideas would be appreciated....  Maybe I miss the obvious.

https://cdn.mos.cms.futurecdn.net/RNaW48QkpnKqTo9WtrQ3WV.jpg

[JHCC]

I'd recommend fullering in the grooves between the ridges, and there are a couple of ways that spring to mind. The first is regular top and bottom fullers, especially if you have or can get someone to strike for you. You can also use a top fuller by itself, using a wooden block (perhaps with a groove to hold the workpiece in place) as an anvil, so that you don't damage the details on the other side from the working face.

Now, the cute way to do this would be to make a spring fuller to fit in the hardy hole, but instead of the usual constant radius round bar, you can taper the working surfaces, so that you have an infinitely variety of radii from one end to the other, thus:

You would then fuller in your biggest radius where the round bar has its full width, and then successively fuller in the smaller radii, moving incrementally down the length of the working face for each size of groove.

[George N. M.]

Scott, what I'd do is use several sizes of rounded end chisels.  I'd draw out the shell (I'm not worrying about the body or tentacles), strike the valleys between the ridbes at regular intervals on both sides (may be use a top and bottom fuller to get them exactly opposite) and then roll it up.  

There were LOTS of different types of ammonites during the Cretaceous Period.  Some had elaborate shells and some plain, Sizes were up to about 3' in diameter IIRC.

They are named after the Egyptian god Ammon who sported a pair of rams horns on his head.

"By hammer and hand all arts do stand."

PS I like John's idea of a variable geometry spring fuller.

[Latticino]

If it were me I'd just use a piece of rebar to simulate the ridges and taper it only on two faces.  Then I'd roll up those faces into the spiral. It might not taper in "depth" like a true one, but I think you would get the illusion pretty well.

[arkie]

Scott, here is a photo of a slabbed ammonite.  I don't know if it's too detailed for your forging.  There is no copyright...this is a personal sample I own in my collection of fossils.  Feel free to use it as you (or anyone else) wish.

 

 

[George N. M.]

One of the interesting things about ammonites is that over geologic time the septa (the dividers between the chambers) went from very smooth and simple to wavy (like Arkie's sample) to extremely complex, almost a complex fractal pattern.  I have never heard a decent explanation for the phenomenon.

GNM

PS One of the many reasons I miss Thomas is not having another old geologist on the forum to either confirm something or call BS if I misremember something.

[JHCC]

34 minutes ago, arkie said:

Feel free to use it as you (or anyone else) wish.

I think I might borrow that as the design for another repoussé practice piece.

Also, here's a fun little video of someone forging both an ammonite and its parent "rock":

 

[Frosty]

Oooh, I like this one! The head and tentacles are easy, so I'll concentrate on the body. I think I'd forge the shell straight then roll it as suggested already. The easiest way I know of to get the sharpish ridges between the rounded lateral flutes is to forge pipe. It'd take a couple die sets, first a set of swages to taper the pipe, the next a set of fullers to make the lateral flutes leaving a sharp border between flutes. That alone might be enough to form sharpish ridges but if it doesn't then driving it inwards from the ends should exaggerate the ridges. I'd do that one section at a time to improve my chances of keeping it under control.  

I'm thinking I'd taper the fuller set to  make it easier to accommodate the tapered body. I think I'd make one of the adjustable tip/bottom fullers and just adjust the height with the taper. 

I'm sure I'd have to make a number of test pieces to get all the features good enough, combined and rolled.

Then make the head and tentacals the way Bryan Brazeal showed us for making a squid. Forge weld 9 lengths of square stock at one end and forge the standing lengths into tentacles. The eyes and mouth are just punched or chased details. 

The 9th tentacle? forge it into a little fish or something edible the ammonite caught and is pushing into it's mouth.

Frosty The Lucky.

[anvil]

I'd do it different than all the other suggestions. Going on your pic.

1: Make the detail tool you are talking about. A hand held tool with a 3 dimensional  rectangle at the working end. The rectangular face is perpendicular to your anvil face when the tool is laying on your anvil. Now forge that face back so it is at an angle, no longer perpendicular, to the anvil face but the top edge is set back. No sharp edges or corners, especially the bottom edge and corners. It's not a cutting tool, it's a moving material tool.

2: taper the square bar and champfer the edges to start getting the slightly ovaloid(??) shape

3: now the fun part.  I would work at some angle with the length across my anvil using a stand, an s hook, and a heavy weight. For me this will hold my work secure and I don't have to continually adjust the pritchell type hold down and leave both hands free. Now the tool. What you are going to do is drive up the leading edge of the scale so its above the top face of your stock. Think Yellen and check how he creates leaves on the sides of large square stock. I did a large acorn this way where the shell separates from the kernel. Start at the center, then work outward twards the sides.  While you are working twards the sides, maintain your angle but spin the tool shaft slightly around its axes as you work outwards. Don't forge too much, little bits at a time works. Now work from the top down, bottom edge facing out twards the back of the valley and start working on the lateral radius and flat valley bottom  This will leave a natural relatively flat raised top edge that tapers down to the bottom valley. spinning the tool in your hand will flatten the wide valley bottom and start making the lateral roll. Thats the plan, my man and where I would start. Starting here and a bit of playing around on this technique may show you where slight edge, bottom, and face changes will make a better tool. All in all, you may need a tool variation or two in the working end to get this detail. I think with a tool or three variations you can do all the details and have the flat radius"d valley bottom get progressively smaller. 

4: My instinct is to do the side grooves last, but maybe not. 

A great project to grow the uniqueness of your scrap pile,,, or wall hangers from the initial test pieces.    

The interesting thing here is that the instinctive tool shape would be concave. Not so, a concave shape has a single radius and you are stuck with it. Great if that is what you want, but It doesn't work for an ever changing radius. So a slightly convex shape actually works better.    

 

5: Roll it and scroll it.

I just noticed that George had a similar approach.

[JHCC]

13 minutes ago, anvil said:

ovaloid(??)

"Ovaloid" means "egg shaped" and usually refers to a three-dimensional solid.  Since you're referring to the workpiece's cross section, either "oval" or "elliptical" would be appropriate here.

[anvil]

Yea, I at first thought oval but the sides seem a little flat for an oval,,, lol, in this case put ovaloid as a variation on "ovalish",,,

[Scott NC]

  Thanks for all the input.  Now I'll have to see what works.  I think I'll try each idea, I have a lot of time.  I have stock to work with and my scrap pile looks a little lean to me.  I'll stop adding to it when I find what looks right.  The tentacles will be the fun part anyway...   I can't help but like the twisted shells in the video, though.  

  Thanks Arkie.

[Scott NC]

2 hours ago, anvil said:

Think Yellen and check how he creates leaves on the sides of large square stock.

  I can't find this.  I have one book on him.

[Irondragon Forge ClayWorks]

I might try using the MIG welder to raise the ridges, it works rather well on octopi tentacles.

I can't control the wind, all I can do is adjust my sails.

[Frosty]

I've read it twice but I can't visualize what you're saying Anvil, just about when I think I do you describe doing something that doesn't fit my picture. I'm not griping you but I'd sure like to add the technique and tools to  my personal kit.

Maybe I'll read it again in the next day or two and if I still don't get it I'll ask again or PM you. Okay? 

Frosty The Lucky.

[arkie]

9 hours ago, Latticino said:

If it were me I'd just use a piece of rebar to simulate the ridges and taper it only on two faces.  Then I'd roll up those faces into the spiral. It might not taper in "depth" like a true one, but I think you would get the illusion pretty well.

I'm with the rebar crowd, LOL.  A bit lazy, I am.  When I make my snails (could be small ammonites, I guess), I grind the ridge off the rebar, then coil up the spiral shape.  Ammonites and snails don't have ridges down their backs.

[Scott NC]

   I think I will try the rebar route first and see how it looks, I get stuck on "it's gotta look like that" sometimes.  Maybe I can embellish it with hammer + chisel, or some weld beads, who knows.  I have some smaller size to experiment with and if it looks good, I can look for bigger size.  I never actually had to look for rebar before; it always just gravitated to me......  But I bet bigger sizes are hard to find.

  It's nice having other ideas mentioned here to fall back on or try in the future, though.  I really like the idea of an adjustable taper spring fuller, sounds like a tool I need anyway and fun to make....

[anvil]

Words are harder than the actual work. I'll find the tool and take some pics. 

What I described is from Daryl Nelson, Fire Mountain Forge and his techniques for making animal heads. I've noticed he has new vids on youtube. They are worth watching.

[JHCC]

Yes, they are. 

19 hours ago, anvil said:

Yea, I at first thought oval but the sides seem a little flat for an oval,,, lol, in this case put ovaloid as a variation on "ovalish",,,

“Oval” doesn’t have a precise mathematical definition the way “ellipse” does*, so you  would have been safe to use it. If we want to be linguistically creative, I would suggest “ovalesque”!

 
 
*Especially when talking about cricket, whose playing field is often called an oval even though it can be of almost any size or shape. 

[Frosty]

I don't know what shape an ammonite shell's cross section is, the outer curve is elipse-ish but almost more like an airfoil. The inner is flat or even convex to a degree. Think an egg with the wide end pushed in, flat or convex.  Of course this all changes for the inner coil's cross section, In a forged representation. But in reality the shell is already formed when the next one grows around outside it so it's the new growth that conforms to the existing shell. 

This leaves us the challenge of shaping the cross sections so the outer coil's contact with the inner is wider, almost like the inner one is embedded slightly and the outer profile is narrower but embedded in the next out. 

I have a number of ammonite fossils and none have the apparent form I describe above, the curve coil to coil is a pretty uniform without defined borders. Garden snails have more ring definition and texture but Ammonites lived a long time and took many different forms, I have a fossil of one close relative, the Orthoceras. And heck your garden snails are distant relatives as are Nautilus, squid and octopus, etc. heck marine mollusks. 

Ammonites were so common and varied we can get really creative. Maybe some had spikes, maybe beaks, who knows. It's a fertile field to forge in. I'd say the only definite "rule" would be that it's recognizable as probably an Ammonite.

Right now the idea occurred to make one between knee and waist high you connect to a hose and the tentacles flip around to "sprinkle" your lawn while the "body" rotates slowly in place. 

Ooh how about a mower deck, cutting  discharge between the tentacles! 

Frosty The Lucky.

 

[Scott NC]

15 minutes ago, Frosty said:

Ammonites were so common and varied we can get really creative. Maybe some had spikes, maybe beaks, who knows. It's a fertile field to forge in

  How about a paperclip shell for some complexity?  Not really a recognizable ammonite form but an ammonite just the same.  I already broke your "rule"......

https://www.google.com/amp/s/phys.org/news/2020-11-ancient-squid-like-creature-paperclip-shaped-shell.amp. 

  Maybe Rainbird would be interested in that sprinkler design..

[Frosty]

OOH! Would that make an excellent paper towel holder or creep out the guests who used the toilet paper!

Now my mid is all aboggle, thank you very much.

Frosty The Lucky.

[anvil]

Lol, what a hoot! Defining one if these thangs is like defining a snowflake,,, each is different. I'm challenged enough with Scotts original pic. 

To keep it simple, like you first said, my way would be with some variation of hammer and chisel.

How would I make and use them? Whatever my description brings to mind,, make one, then put it where ya thinks it ought to go and hit it as hard as you think will do the job,,,repeat til either your scrap pile is over flowing, you'r burned out, or you like what ya done...    

[LarryFahnoe]

I'm in the beginning stages of my journey in smithing & find it just fascinating to try to visualize the suggested approaches to this very interesting puzzle. Will be interested in seeing a pic of the tool you're thinking of Anvil. The natural world has always intrigued me & I'm particularly interested in the forms of growing things, but this is just a neat idea! Years back I collected a bunch of Ammonite fossils, so now to visualize making one.

22 hours ago, Frosty said:

Right now the idea occurred to make one between knee and waist high you connect to a hose and the tentacles flip around to "sprinkle" your lawn while the "body" rotates slowly in place.

--Larry

[Frosty]

Think that's good you should hear about my shaggy dog sprinkler.

Frosty The Lucky.