Let me start with telling you really quick how I came upon this massive chunk of wood that I used for my table top. I had just purchased my first lathe and I was on the lookout for some wood to turn, and I saw a tree service cutting down this great big tree. I asked the guys if they could hook me up, and they were super cool and helpful about it all. I ended up getting lots of smallish branches and stuff for turning, and finally got this piece cut off the trunk to try to use for this table. That was three years ago.
Some say to give a slab of wood a year to dry out for each inch it is thick. This piece is three inches thick, therefore I gave it three years.
This was a two part build. Stage one was flattening the slab and securing the cracks. Stage two was building a base sturdy enough to hold this top. It was rather heavy, so I figured I'd try to build it super stable. Let's get started.
Step 1: Secure the Cracks
Like I said, this piece of wood has been sitting in a corner for three years, and when I pulled it out, a once tiny little crack had spread out and become huge. So I started by filing it down as smooth as I could, then sanding it a bit to make it more presentable. Next I wanted to put some bow ties, or butterfly keys, in not only the huge crack, but also the small ones to prevent them from spreading out in the future.
I just cut out some bow tie shapes on my band saw. Then I set them where I wanted them to go and traced out their shape. I used a router to remove most of the wood and finished it up with a sharp chisel. The chisel was mainly just used to square up the corners that were left round by the router bit. After you get a really snug fit, you can put some wood glue in there and tap the bow tie into place. I then add more wood glue and smear in some saw dust to fill in those little spaces where the fit is less than perfect.
Step 2: Flatten the Slab
This part of the process sounds really simple and actually is as easy as it sounds, but it is extremely time consuming and rather laborious. I added a video above showing a really simple jig that I made to hold a router that you can pass back and forth over the top of your slab, taking off a tiny bit of material with each pass until you have it all level and pretty much smooth.
Then you can come back with a really aggressive belt sander to remove any router marks left behind. After that, you can move on to a random orbit sander. Which I decided to work through the different grits, starting at 60 and working all the way up to 220.
I didn't try to get it perfect at this point, because I knew I would be coming back to sand a bit more before final finishing.
Step 3: Build the Base
For my base, I purchased two pieces of cedar, because I had originally planned for this to be an outdoor table and I figured cedar would hold up to the elements. I got one 2x4 and one 4x4.
I wanted to do a farmhouse style table base with an "x-frame" look. It's the style where there is an X shape sitting on the floor and another X shape touching the table top. The two Xs are connected by a column, then each corner of both the Xs attach to the column via 45 degree cuts. I did a horrible job explaining that just now, so look at the picture for a bit.
I cut the 4x4 first, to serve as the central column that the other pieces would attach to. Then I cut the 2x4 pieces to serve as the top and bottom X pieces. Last is setting the miter saw to 45 degrees to cut the remaining 8 pieces.
For the two X pieces on the top and bottom, I cut half lap joints on the table saw, which was my first time doing this technique. It was very easy and made for a very strong joint. After they fit together, just glue them up and clamp them to sit for a while. I let them sit overnight and came back to it the next day.
Finally, you just need to assemble all the pieces. I used wood glue and screws, and I made sure to countersink all the screws so that I could put in a piece of dowel to cover up and screw holes. This step really gave it a much more finished look at the end.
Step 4: Finishing Touches
I added epoxy to the really small cracks that didn't require their own butterfly key. I mashed it in as good as I could and let it sit for a while before sanding it smooth. I cut all the dowels from my screw holes with a flush cut saw and then sanded everything smooth.
I finished everything with polyurethane that I diluted with mineral spirits. This makes it a bit thinner and easier to apply. I put it on with a foam brush then hit it with a hair dryer to try and remove any air bubbles. Between each coat, I sanded it very lightly with 220 grit sandpaper. Three coats and I let it sit overnight. Then I came back with paste wax and applied that with a clean rag. I let it sit on there for about a half hour and then buffed it out, leaving a very nice, smooth finish.
Finishing is something I've been trying to make an effort to improve my skills on. I'm getting better with each passing project, but there's still much room for improvement on the next one.