I was commissioned to build a dining table using an awesome slab of Walnut. I thought it would be interesting to pair w-beam legs with the slab. Have a slight industrial feel. Having the table legs intersect, or "crash" through each other would be a visual feast, and quite a challenge. Below the original design narrative:
This slab of wood is massive, and thick, dense and solid. It conveys permanence. The grain shows age and tumult, but more than that shows wisdom. The creases around a mother’s eye, the rough hands of a grandfather; aged yes, but ultimately imbued with love. To dine upon this slab is share in ritual and celebration, the tree envelops the guests in a silent embrace. The tree will be cleaned, and finished to expose its wonderful grain, but with reverence, not with a showy, high gloss, but with a humble satin varnish; protection from the inevitabilities of dining, but respect for the wood.
balance the mighty slab, a pedestal will be constructed that equals the tree’s visual weight. Powerful steel I-Beams will be made to collide, pass through each other, ultimately to support the table top. By bringing the legs to the center of the table top, the visual size of the table will be somewhat reduced. The table will show both lightness and robustness. The heavy slab seems to float over the legs, the strong beams intersect effortlessly.
Original Concept Render
The Finished Live Edge Table
The Build Process
For many more pictures, please check out this google photo album.
I began by measuring the slab at fixed points so I could create a rough solid in CAD to visualize and plan the legs.
The legs were positioned in space and then intetsected in such a way that they could be assembled in a puzzle like fashion. There would be one leg with no cuts and it would serve as the "key" to lock all the parts together.
Here is an example of one of the legs on all four sides showing the crazy compound cuts that were required. For certain legs I ended up cutting them into two sections and re-welding them later to ease the fitting process.
A 3D printed model of the leg concept so that I could wrap my head around what went where. It was tricky to visualize this through building it, as everything was at a strange double angle to everything else.
I used a CNC router to cut specific angle jigs to set one part of the compound angle for cutting the ends of the legs.
The other angle was set on this big band saw using a digital angle gauge. The beams were clamped to the power feed table.
Then fed through slowly. These cuts turned out great. After the initial cuts the leg was flipped over and the legs were cut in the other direction. The result was two compound angles with parallel faces. One to sit on the floor, and the other to support the table top.
I cut card stock templates to scale of all the faces of the legs and transferred them to the beams with marking dye and a scribe.
Then began the horrendous process of plasma burning out some of the metal then grinding, grinding and more grinding to get all the cuts to fit. Here is a partially cut beam.
I ended up dismantling a abrasive chop saw to get the power and depth for grinding in some of the cuts. This was a lot of work.
Good thing these beams were extraordinarily heavy, it made the constant set-up and tear-down of the assembly really easy! (kidding) I test fit onto a separate jig plate with little hooks to hold the beams in place, while other elements were ground to fit.
Once all the parts were fit I tacked everything, and began filling in welds in various areas, eventually doing all the seam welds I could reach. Some of the welds were left exposed. Some were ground down and sanded in to return the beams to continuous sections.
The whole frame was then sandblasted to remove weld scale and rust, as well as blend in grinding marks. After grinding, this was the second most onerous task of this project.
And taking the third would be sitting out in the freezing cold with a weed torch, heating up the whole frame and then rubbing it with oil for a blackened finish. This finishes up the bottom of the table.
For the top, I began by repairing any loose areas of the slab and then filling every crack and check with epoxy resin. This required several sessions of application, sanding and re-application. I also had to do this after the main flattening operations.
The bottom of the slab was decked with a fly cutter on the CNC router, then a recess was cut for the support plate.
Additionally, two grooves were cut for supporting braces.
I used a custom made edge plane thing (top left) to help find the high spots and slowly fit the grooves so the braces would slip fit in.
The braces were then fit into their slots.
Then they were welded together along with recessed threaded inserts to accept the legs.
Originally I thought it would be cool to heat color the braces and leave them exposed, but after installing them I wasn't blow away by the look. Even though this would not be seen under the table, it still bothered me.
The solution was to fit walnut covers into the brace recesses and sand them smooth with the bottom. After the finish you can barely see them.
Then I moved on to decking the top of the slab.
Once the slab was roughly decked, I moved on to using a belt sander to remove the major machining marks. I then moved on to stepping through various grits on the orbital sander to make the surface extremely smooth. All the surface bark and debris was removed and then the edge surfaces were smoothed with a die grinder and cleaned and sanded. Finally I installed a couple of cocobolo bow ties in one main crack on the side.
After ensuring all the cracks were filled with epoxy and everything was sanded to perfection I applied the finish. Three coats of Waterlox to each side. Here is coat number one.
And the second coat:
And the final coat, awaiting to be mated to the finished table legs and delivered to the customer!