Intro: Shopbot + Birch Ply = End Table
As a primer for a larger project I decided to take on a small laminated end table. The project came together from start to finish in an afternoon, the design was focused on creating a simple form using efficient nesting of sheet goods on a shopbot CNC router.
Step 1: Design
The concept behind this small project was to get a sense of the cutting, construction, and finishing processes of laminated plywood. This experiment is in the service of a potential larger project, so this should be seen as a rough test of principles and materials.
The design was a simple extrusion of plywood with the end-lamination's sprouting legs to support the top. The goal was to create something as simple and smooth as possible using the process of CNC cutting and stacking materials.
Step 2: Layout and Setup
Nesting on any CNC job is essential both in terms of economy and resource responsibility. Cumbersome features like these continuous legs often pose problems to layout efficiency, but in this case the top pieces fit fairly well in between the legs.
A second detail that I incorporated was the addition of CNC drilled holes for dowels, that allowed the pieces to stack neatly, eliminating more margin of error on my part. The final capping legs had holes that only extended 3/8" into the 3/4" material for a flush face finish. All other holes were through-holes.
Attached is the DXF file of the profiles, these vectors still need to be post-processed.
Step 3: Cutting
Using a 4' x 3' section of a 4' x 8' sheet of 3/4" Baltic birch plywood the sheet is setup on the shopbot.
The original DXF is imported into V-Carve and toolpathed. V-Carve is a super simple and easy-to-use tool that allows vector cutting to be exactly and simply executed. It has functions that allow for tool offsets, material offsets, tabs and fillets.
Step 4: Fabrication / Glue-up
The best part of this whole process was the indexed dowel holes. They took almost no effort on my part in the computer and made the layup a breeze. I simply glued the dowels into the first holes, then slid each following layer on with a bead of glue, clamped and ta-da!
Step 5: Sanding
The sanding actually wasn't as big of a pain as I thought it might be, because of the use of the dowels there were no extreme variations in the surfaces, I used an 80 grit pad on an orbital sander and knocked down the imperfections. Once the surfaces were acceptable I moved onto sealing the wood.
Step 6: Finishing
I applied a coat of polyurethane out of an aerosol can and wasn't pleased with the coverage. Considering how much end grain their was to cover I moved up to a liquid applied polyurethane.
After two coats I was satisfied with the finish.
After the poly dried I lightly sanded the surface with some 600 grit sandpaper until the final surfaces were smooth.
Step 7: Final Product
Stack up books and enjoy!