Many months later, I finally made the time to finish this project.
Step 1: Preparation
The most time consuming part of the process was definitely the design, as I wouldn't be entirely satisfied with the result and ended up redesigning multiple times until things were refined properly. After the initial sketches I created a computer model just to be certain of my dimensions.
Step 2: Redwood Table Top
Once the boards are all cut it is time to glue and clamp. Heavy weights will help, and let sit 24 hours. When the top had dried I added runners around the perimeter and lateral supports underneath in the middle. The increased depth from the sides gave rigidity and stability.
The top surface was pretty smooth, but still needed some hand planing to even everything out.
The opening in the middle needed a steel insert (you'll see...).
Finally, a steel band went around the perimeter (1.25" if I recall) with countersunk holes to attach it to the table. This band helped with the overall industrial look as well as hide all of the joints. Since this table was going outside, I opted not to inlay the steel since I wasn't sure how much expansion and contraction to expect from the wood, and gave it some wiggle room.
Step 3: Nice Legs
There's a lot going on during this step, so I will put annotations in the images. Roughly, the process went: measure, measure, cut, clean, deburr, descale, drill, tack, weld. Having a jig for the welding helped ensure the two sides were identical and square.
The bottom plates for the foot mounts were cut on the water jet for a perfect, snug fit. We did not have a tap and die set large enough for the over-sized hardware, so I had to weld a nut to the plate for the feet to be adjustable. Stainless steel hardware is better because if it is zinc plated you must remove the zinc before welding.
Step 4: Chairs
For the cross bars, I planed down scrap wood to make sure the bars were consistently (and quickly) centered.
In order to get the seat portion done correctly and quickly I utilized my computer model to set up a file for the CNC router. This allowed for the seats to have that subtle indent for your rump -- in less than 30 minutes. Since I used the same digital file for the seats as the welding jig, everything fit together beautifully and I got to skip many headaches!
I routed all the edges, and then sanding was a breeze. There are a few assembly pics included here, but I'll cover the finish work in the next step.
Step 5: Finish Work
The patina contains iron oxide (not the lovelies of smells) and the stained material must be rinsed and dried for the chemical reaction to stop. Follow up with polyurethane right away to prevent further rusting. I didn't want the steel to be completely black, just darkened enough that it wasn't so shiny as raw steel.
For the wood, while I wanted to retain the imperfections, certain knots needed to be patched in order to prevent them from falling out later on. Use the fine dust from the orbital sander catch bag as the base for any wood filler. Start with a liberal amount of wood glue and slowly add the saw dust (stirring as you go) until the paste is no longer glossy.
To finish off the wood I went with danish oil and applied it with a 100% cotton rag (ie: old shirt). Apply evenly and with the grain. Allow for the oil to fully penetrate the wood before continuing. While the oil supposedly has a sealing agent in it already, I opted to add polyurethane to give it a little extra protection.
Step 6: Final Product
I just couldn't justify thousands of dollars for a table and chairs, especially when I had the materials literally on my doorstep and TechShop just down the street. Plus, I was able to make everything taller than normal to accommodate me being 6'2". Not only did I save a ton of money, but the custom design fit my needs better than anything on the market!
It's a rich color now, but I'm curious to see how it ages in the coming years, as I intend to have this for set for some time.