After experimenting with rapid box construction on the second day of ENGI 210, we were tasked with building another box for our second homework assignment. It had to be a quality box this time – that meant no jagged edges and no random pieces sticking out. This box had to be made of wood, must be rigidly fastened at the edges/vertices, and must involve the use of a router during construction, to smooth the edges.

I chose to create a 6” x 6” x 7” box using 1/2” thick plywood. As part of the perks of being in ENGI 210, I had access to an entire stash of plywood sheets lying around in the wood shop. My box would consist of four 6” x 6” square pieces attached to a 6” x 7” base. To make sure each rectangle was cut to the correct length and had a proper straight edge, I used the wood shop table saw with help from Fernando. I had never used the table saw before, and was surprised by how easy and smooth it was to cut the pieces!

Next, I used the router to round the edges of the pieces so that my box would have smooth edges when fully assembled. This took some planning. I wanted to keep some edges flat for ease of attachment, and only round the edges that would make up the outside edges of the box. For example, I rounded all four bottom edges of the bottom piece, but only the top edge on some of my side pieces. With the router, it was important to slide the wood across the drill bit with sufficient pressure but not at too slow a speed, to avoid burning the wood.

With all the pieces cut and routed, it was time for assembly! I debated for a long time on my method of attachment. Should I just screw my pieces together with a regular drill, or do I turn to the fancy, cooler-looking, and blue kreg jig? Ultimately, the trusty drill won out. After trying the kreg jig with some scrap plywood and running into issues with securing the wood, screwing into the kreg jig hole, and wood splitting, I decided that countersinking screws from the outside would be my safest option. Split wood and questionable kreg jig holes cannot do for maximum box beauty.

I selected flathead screws with a length a bit over twice the thickness of the plywood. I used a corner clamp to secure pieces of wood during attachment. Before screwing, I marked the location of the holes using pencil and made them all about 1” away from the edge. I also drilled pilot holes using a 1/8” drill bit as a guide before inserting the screws.

When fully attached, the box had four screws on the bottom, and four screws on the left and right sides. Some of the screws were nicely countersunk against the surface, while others got slightly stripped by the drill and annoyingly protrude a few millimeters above the surface. The natural imprecision of the table saw and the slight warping of some of the wooden pieces (thanks Houston weather) made it so that the edges didn’t perfectly align after drilling. I used the belt sander to sand down any protruding edge, and used sand paper to further round the corners and edges.

Of course, I wanted my box to be smooth and shiny at the end, so I spent two days sanding my box further with fine grit sandpaper (so much sawdust!), and painting on two coats of polyurethane gel to create a glossy finish. It was totally worth it.

 

Cost analysis:

• 1/2” x 2 ft x 2 ft plywood sheet: $10
• Box of screws: $7
• Assorted grit sandpaper: $3.37
• Miniwax Polyurthane can (32 fl oz): $11.98
• Machinist salary/hour: $18.90 (assuming this includes access to power tools/other accounted for machines. Only for assembling box, and assume that post-processing like fine sanding is done by free student laborers)

Total materials cost estimate: $32.35

Total cost estimate (including labor, tool usage): $51.25