Continuing with the first batch of wood from the sawmill and along with the other furniture changes it sparked the idea to make a new coffee table. The previous table had been passed-on from the previous owner of the previous house, nothing special about it, overdue for replacement. There’s a nearby lake I wanted to incorporate into the design, and by far the toughest part of this project became obtaining its bathymetric data. The entity that controls the lake was helpful with a records request but ultimately their best data was a medium resolution plot, shared via pdf. There were some hints from various navigation and fishing apps that better data might be out there, but after a lot of messing around with importing and converting this turned into a dead end. I eventually resorted to sending the pdf provided by the govt through an image vector tracing tool, followed by many hours of manual cleanup. This gave a single contiguous vector curve for each depth increment that I could then assign to a CNC machining operation.
I tested the CNC programming on a scrap piece of plywood before sending the oak slab through. The table is the full 4ft width of the CNC but wider than the CNC’s depth. To get around this problem I ran the carving on the middle section of the table before completing the full slab glue-up. When the full slab was together I traced the large radii using a yardstick as a compass and connected these with smaller corner radii. This outline was cut with a jigsaw before being belt sanded and rounded over with the router. Then final sanding and finishing. I cut two small sections of steel angle and secured them to the bottom of the table across the slab joints with screws in slotted holes. This will help hold the table flat while still allowing some seasonal wood movement. Last step was attaching some off-the-shelf hairpin type legs.