Elbow pattern help

[Halbrust]

I'm creating the pattern for my first piece of armor ever. It's an elbow cop that will be used as hidden (or mostly hidden) armor. It's basically a soupcan knee for the elbow.

I used a manilla folder to get the shape and forming right. It looked and felt pretty good.

Let me show you a basterdized version of a picture of the pattern and then I will ask my questions.

The outer line is the entire piece of material I used to fashion the piece.
The inner image is... the shape it created after I creased and folded the the material to fit correctly, then cut it in hald and matched the ends up flattened it letting the center overlap.
The 4 triangles are the material folded out of the way.

What shape metal should I cut to achieve the final piece? The inner, the outer, half between?



Remember that this is my first attempt and my terminology and such may be incorrect. I will happily answer any questions that will get me closer to my goal.

[Godric of Castlemont]

Couple of questions so we can try and help.

Why did you cut the piece in half? Was it re-welded after that?

You said you creased the material to make it fit, was that the triangles you cut out?

What exactly is the question, how to make the cop fit or where to cut some more, and if the latter what is the goal of the cutting?

I am sure some one here has some ideas but a little clarity will help us help you.

[Halbrust]

Has not been made except out of a mannila folder as of yet.

The triangles could be cut out and then welded. If I did that I'd have many less problems and quetions. But I want a one piece dished elbow, and I can't weld.

[Konstantin the Red]

Halb is a Dagorhir, if that clarifies any thinking.

If you can't weld, budget some money to pay somebody to do the welding for you.

Metal doesn't fold quite like origami paper. Your problem will be keeping such folds staying flat; they are unlikely to. It's thicker and the outside of a fold comes very much into tension, so the bend is much inclined to open out again -- all the more so with two such bends near each other. This is less of a problem parallel to the edges of a piece of metal, where you really can fold it over flat and have it stay.

The old heads around here will tell you just dishing one piece of metal isn't really going to get an elbow cop to the depth it needs to be -- though that's good enough for a knee. Cutting out then dishing two halves (distal and medial, seaming together at the elbow's point), then having some guy in a truck come by and weld them together for you (or, cheaper, take 'em to a welding shop that is willing to take on a little side job in fabbing up something of sheet metal) -- that's practicable and effective.

Another budget item for you, as an alternative: a community-college welding course, with their well equipped shop and about sixty dollars in tuition and lab. (Scare a man with a lit welding torch and he's upset all afternoon; teach a man to weld and he can blister himself for the rest of his life.)

[Halbrust]

To clarify, this is for SCA use.

[Konstantin the Red]

This sort of thing used to be kluged by non-welders in the SCA by cutting two deep V notches along the vertical centerline of the cop (the short axis), radiusing the apices of each notch with a drill, and pushing the edges of the V notches together to be riveted closed. Even making one side of each V notch into a tab through which to put at least one or two small rivets. This was more popular in plastic or hardened leather. Leather could be stitched shut to quite good effect.

The great majority of us simply bought cops and did everything else ourselves.

[losthelm]

For a simple elbow cop you should be able to just dish it.
A simple form "AKA dishing stump" can be made with a bit of lumber or the bottom of an oxigen welding cylinder about 25-30 on Ebay.

What metal are you planing to use?
I would sugest 16 guage mild steel.
Stainless can be a little much just starting out.

To give yo an idea on scale and process.
http://www.armourarchive.org/essays/poleyns_krag/

Adding the flute is not needed.

[Sean Powell]

Ok, you want to make a wingless, low-profile elbow that is SCA legal and you want to construct the pattern yourself and you can not weld.

I take back any previous comments about a great-helm being the easiest thing to pattern. THIS is the easiest thing to pattern.

Put on your elbow pads. Bend your elbow and with a flexible tape measure have a friend measure the distance from the inside point to the outside point plus any extra that you wish to cover. On me that's maybe 10" (I don't have pads near by.) Now measure in the other direction the distance you want it to cover.

On a piece of paper draw and elipse (oval, whatever) that is whatever long by whatever wide. Cut this shape in 16ga steel and debur the edges. Drill a hole in a block of wood, grab your ball-peen and pound the steel into the hole. In the beginning it will move easily but will only want to curl in one direction. Force it open and repeat. Eventually you will have a lumpy mass that is almost the right size.

If you have an anvil it is more productive to hammer from the inside to push out any low spots. If you don't then place the elbow over a ball (even your ball-peen in a vice will work) and hammer down the high spots from the outside.

Eventually you will have your very own first piece of armor... and will realize that people make armor because we are insane.

Have fun!
Sean

[Halbrust]

Sean, so the outside will suck in as I dish the center?

I'll have access to a nicely stocked armoring forge, I just want to make sure my patterns are ready before then.

And for whoever asked, I'll be using 16 guage cold rolled steel.

[losthelm]

The forge will not be nessicary working it cold will help make the final product harder.
If you have access to a decent shop you can probily pound thes out in under 3 hours.

[Konstantin the Red]

However, working it hot will make the initial roughing-in go faster and easier, and your metal won't workharden. Plenty of time to get workhardening into the picture in final tweaks and the planishing. This is one of those times when hotworking is okay even if inexperienced.

Does that forge come with anyone who can show you raising, or help steer you down the right path at raising? You want an elbow-cop's curvature pretty deep, with the ends that ride on either side of your elbow joint comparatively flat.

What I was saying earlier applies to working the metal cold. Roughing it in red hot is a completely different game.

[Sean Powell]

Sean, so the outside will suck in as I dish the center?

Two things will happen as you dish and they amount that one happens more then the other depends on the metal properties, thickness, distance in both directions, face of your hammer, shape of your dish and other factors.

If you cut a 4" square of 16ga steel and scratch 1" grid lines on the face and then dish it you will notice that at about the curvature of a soccer ball The sides will be sucked in like ) (. If you measure if with a flexible tape accross the gap is may be 3.5 and over the arc maybe 4.1. If you measure the corner to corner distance you will see proportionally more stretching. If you look at the grid lines in the vertical and horizontal thy still cross at 90 deg but at the grid lines on the angles will decrease from 90 to maybe 75.

If you keep dishing deeper you will notice more stretching, but primarily on the diagnal axis. The extra material stabilises it's location and prevents it from being sucked into the center. From the side the metal will tend to flow into the dish more instead. Eventually as you go from the diameter of a baseball down to a tennis ball, the curvature is sharp enough that the deformation is amost all stretch regardless of direction.

If we apply the same principles to an elbow: In general we can consider the pinky to shoulder direction to be like the vertical and the metal will want to flow into the dish. The long direction is like the diagnal and is more likely to stretch... but will still generally flow into the dish until you get to your deepest dishing.

Stretching isn't bad. Remember, you can always re-cut it smaller after dishing but it's a pain to make it larger.

Happy hammering!
Sean

[Halbrust]

However, working it hot will make the initial roughing-in go faster and easier, and your metal won't workharden. Plenty of time to get workhardening into the picture in final tweaks and the planishing. This is one of those times when hotworking is okay even if inexperienced.

Does that forge come with anyone who can show you raising, or help steer you down the right path at raising? You want an elbow-cop's curvature pretty deep, with the ends that ride on either side of your elbow joint comparatively flat.

What I was saying earlier applies to working the metal cold. Roughing it in red hot is a completely different game.

Full of armourers and metal pounders. I just wanted to make sure I had a decent pattern before I show up later this month.

[Konstantin the Red]

So you're doing up your own patterning as an exercise in that skill?

[Halbrust]

Yes, and it was what I was told to do by the one mentoring/guiding me.

[Konstantin the Red]

Sounds like a good exercise. Yeah, the blank for an elbow cop isn't any very complex shape. Even cops with articulations bracketing them aren't really any more complex. Most cop patterns look like a pair of parens () anyway. The fan is just an add-on from there. Many people like to avoid getting stress-cracking problems or dealing with a fan in the way by welding or riveting the fan into place after the cop is raised/dished.

[Halbrust]

Thanks!
And the more I play with it now the more I'm liking an egg shape. Larger on the outside than the inside.