Alright so here is the video! I try and condense all of my builds into ~8 minute videos while including the relevant steps. There are a few details in the video that I wasn't able to squeeze into the pictures, so if you can spare a few minutes I invite you to check it out.

These were the first chairs I've designed and built, and let me tell you--chairs are difficult! There are so many crucial measurements, and angles required to make a comfortable chair. These are constructed with mild steel and black walnut.

Step 1: The Seat Pan

So, the first step was to make the seat pan. For this I used 3/4" steel tubing cut to 24" length. I cut the tubing on a DeWalt DW872 Cold Saw.
To weld it all together, I use 90 degree magnets and a speed square(If you don't have a speed square, you need to get one). The welder I'm using is a Lincoln Electric 140C MIG welder.

Tools used:
DeWalt DW872 Cold Saw
Swanson Speed Square
Lincoln Electric 140C MIG welder

Step 2: Step 2: the Legs

On to the legs! The front legs were easy as they were just 90 degree cuts, the back legs, however, sit at an 10 degree angle(which required two 80 degree cuts). The legs are made out of 2"x2" square tubing.
Want to try an interesting experiment? Go to a room with no chairs, and measure 17"-19" from the floor, that's how low standard seat height is--If you don't have a chair in the room you will say, no way(it looks way too low). Same as most tables, they are only 29"-31" tall (which also seems ridiculously low if there isn't a table in the room)

Tools used:
DEWALT DW872 Cold Saw
General tools digital bevel gauge
Arrow welding magnet (4-pack)
Lincoln Electric 140C Mig Welder

Step 3: Step 3: the Armrests

On to the armrests. Back at the DW872 cold saw(quite possibly the worlds loudest tool) again, to cut out the 1"x1" angle iron which will become the frame of the armrest.
The next step was to weld up the angle iron, here you can see the aforementioned angle iron welded up to frame the armrests.
Here I am using a 20V max DeWalt circular saw to cut the arm rest sections to length. The wood is 4/4" S3S black walnut. Oh, and there is that speed square again.
More armrest stuff-- I'm cutting the walnut to width(4.25") on my table saw.
Using my DeWalt DW734 lunchbox planer to smooth out the arm rest inserts. I love the smell of walnut!
Here is the mock-up of the walnut inside the frame

Tools used:
DW872 cold saw
Swanson Speed Square
DeWalt circular saw
DeWalt DW734 planer

Step 4: Step 4: Back Support

Here I am actually just tacking the armrest frame in place in order to use it as a reference for the back support. I'll actually have to pop them off to insert the walnut, after I get the back support in place.
Here is that back support I was talking about, I chose 1/8"x2" angle iron as it's the same width as the legs.
So I found this app, called tiltmeter, which is pretty awesome, it's essentially a digital level. After playing musical chairs at some local furniture stores I decided that 74 degrees was my favorite. You can see what I was talking about earlier in regard to tacking the armrests in place for the back-rests. I knew I wanted the back support flush with the backside of the armrest, so I held that in place and actually rotated the bottom of the support in order to get the desired angle.

Tools used:
Lincoln Electric 140C Mig Welder
DEWALT DW872 Cold Saw
Tiltmeter app

Step 5: Step 5: the Stretchers

I feel like the stretchers are really what pull these chairs together(facepalm). But seriously, I looked at a lot of arch bridges for influence on this design, and--well I really like these.The plywood in the picture is obviously just a template, as it's much faster and easier to shape & manipulate wood than steel.
Once I got the template the way I wanted it, I moved over to my plasma table(I actually have a build video on the plasma table on my channel as well).
Here I'm using a Lincoln Electric Tomahawk 375 plasma cutter on 1/8"x8" flat stock. A heads up--the plasma cutter is actually new to me, in the past I've used a jigsaw with a metal cutting bit on 1/8" mild steel, and it actually works better than you might expect.
Here I am welding the stretchers in place.

Tools used:

Lincoln Electric 375 Air Plasma Cutter
Lincoln Electric 140C Mig Welder
I used an old Rockwell bandsaw to cut out the wood template

Step 6: Step 6: Back Rest & Wood Finish

Here I am cutting the back rest boards to length(24"). As for the width, It actually varied from piece to piece in order to effectively use as much of the material as possible as Walnut can be sort of pricey.
For the finish I'm actually trying a new product called Rubio Monocoat. Although it's a little spendy I'm pretty pleased with the experience. It comes in two parts, you just mix them, wipe it on the boards, and wipe it off about 10 minutes later--pretty foolproof application. Oh and it smells like caramel apples, which probably wasn't a good idea.
Here are the finished walnut strips for the back rest.

Tools & products used:

Dewalt 20V circular saw
Swanson Speed Square
Rubio Monocoat

Step 7: Step 7: Metal Finish and Delivery

And the last step(after reattaching the arm rests, was to hand sand the mild steel down to uniform--umm, shininess? Since the chair is mild steel, and well--mild steel rusts when left untreated, I applied 3 coats "clear metal wax" from sculpt nouveau.
Here they are in their space! I personally would have liked to see the chair with tobacco brown cushions, but the grey actually works well in the space.

Anyway, this was probably my most demanding project to date, but it was also very rewarding. If you are interested in the video, I have the link in the first image. Also, if you'd like to stay posted on my work, I invite you to follow me on my instagram "ZHFabrications"

Thank you!

Tools and products used in the video:

Metal work
DEWALT DW872 Cold Saw
Dewalt Flexvolt Angle Grinder
Dewalt DWE 4011 Angle Grinder
Empire Abrasives flap discs & quick strip discs
Lincoln Electric 140C Mig Welder
Lincoln Electric 375 Air Plasma Cutter

Wood work
DEWALT DW716 Miter Saw
DEWALT DW734 Planer
Dewalt 20V circular saw
Preppin' Weapon Sanding Block
70s Delta Unisaw
Rockwell 14" Bandsaw
Old Stanley Block plane

Misc
Dewalt 20V XR Brushless Drill
DEWALT 20-Volt Drill
Swanson Speed Square
General tools digital bevel gauge
Sharpie (12 pk)

Wood & Metal finishing
Mineral Spirits
Rubio Monocoat
Sculpt Nouveau Metal wax