Im building a neckarmour piece(gorget) and wanted to share on instructables, to my surprise there is not a single one for neck armour so here's the first. For the decorations in the center you can check out http://www.instructables.com/id/etching-large-metal-items/ .
Step 1: Tools and materials
clamps(if you need them to secure the metal for sawing)
some drillbits(the size of the rivets)
sandpaper(i used a range of 240 -600 gritt)
boltcutters or hacksaw
grease or oil(i used silicon spray)
anvil(or something hard like a barbell)
gloves(my hands are full of small cuts so gloves are recommended)
eye protection(recommended,but I already wear glasses so there's a smaller chance of anything getting in my eyes)
8 large nails(rivets)
8 washers(same inside diameter as the large nails)
2 straps with beltbuckles(from a watch or thin belt, I got mine from a hobbystore)
a box of small nails(rivets)
Step 2: Design
First of take a look around the internet to get an idea for your design, I googled; neck armour, neck armor, gorget. My design consists of a front plate and a backplate, both have reinforcements around the outer edge. The front and backplate are connected with 2 small straps on top of the shoulders.
When you decided on a style draw a rough shape onto your cardboard in pencil and cut it out. Once cut out fold it in two so you can cut it symmetrically. Try it on now and again to make sure it fits.
Step 3: Tracing your design
Tape everything down using scotch tape and start tracing everything using your marker.
After you traced everything take off the tape piece by piece and fill in the gaps created by the tape.
Step 4: Cutting the parts
Step 5: Shaping
Go slow, just gradually bend each piece until it looks right. Test the main plates(front and back) from time to time to see if they fit.
This is where the (optional) magnets come in, use them to stick the front and backplate together so you can see if they fit together.
Keep shaping the plates until it fits snuggly on your chest and back. When the two main plates fit, start to shape the(optional) reinforcements so that they fit over the edges of the plates.
Now you can stick everything together with some magnets to see how it looks.
Step 6: Sanding (and optional fire)
Alright so we got everything together now we need to remove any paint from the parts. I used fire, just build a fire in the backyard and when its going chuck in one part at a time and wait till the paint is gone.
When you're done or didn't use painted metal you can start sanding everything. I don't think this really needs an explanation, just keep going till its shiny enough to bite(R.I.P. futurama)
Step 7: Drilling
I chose to secure the straps with 2 rivets on each side(so 2 front left, 2front right, 2back left, 2back right) so 8 in total. For the reinforcements I ended up using 8 rivets on each side (16 total).
You need to find some drillbits that are close to(but not under) the size of your nails(rivets). I used 1.5 mm nails for the reinforcements and about 4 mm nails for securing the straps, so I used a 2mm and 5mm drillbit.
So start out by taking your cardboard cutout and figure out where the holes need to be. Fold your cutout in half and drill holes at the correct positions to get all the holes symetrical. Now take a fineliner / pencil and mark the holes on your metal.
If you chose to add reinforcements like me you'll need to figure out where to place the holes on the front and back plates. This is done by first drilling the holes in the reinforcements and laying them over the plates in the correct position and marking, through the holes, the plates.(if a pencil / marker wont work use a nail to scratch the metal)
I marked and drilled the holes by starting in the center, marking the holes, drilling the holes, putting a nail through and securing it with a magnet from the bottom. Then I would mark the next hole and secure it with a nail and magnet, keep this going till you have all your holes marked and drilled.
After drilling the hole for the straps I drilled a hole in the strap and secured it to the lower hole with a bolt an nut and then drilled the second hole using the hole in the metal as a guide.
Step 8: Riveting
Now starts the hardest part of this instructable, the riveting. Start by cutting some small nails to size, double the thickness of your metal plate plus the diameter of your nail. So if you used 1m thick metal sheet and 1.5mm diameter nails its 1mm+1mm+1.5mm=3.5mm long from the bottom of the head to the end. Just make a test piece by taking 2 scrap pieces of the same metal, drill a few holes and rivet until you find what works for you.
When you have enough start by riveting each hole alternating between the left and right side. rivet by softly tapping the top of the nail in circles so it mushrooms out. Keep doing this until all the rivets for the reinforcement are done.
For the straps you need to take your large nails and figure out how long they need to be; the metal + the strap + the washer. for me it was about 5mm. Cut your nails to size using boltcutters / hacksaw and put them through the correct hole, add your strap and washer and rivet it down. Just remember that the strap will give a little, so its better to have a rivet that is a little short in stead of one that is too big.