This time, we were tasked with making a laser-cut, press-fit box.

Before I could cut each face of the box, I had to make some measurements. First was the kerf, the width of wood removed by the cutting laser. To do this, we were recommended to cut out a kerf box, and to push each of the ten cutout rectangles to one side, using calipers to measure the eleven “kerf lengths” of space on the other side.

my cut-out kerf box

I measured the eleven kerf widths to be about 0.037 in., giving me a kerf width of around 0.0034 in. after dividing. Next, I used the calipers to measure the thickness of the wood I was using, which I determined to be 0.185 in. My wood might have had inconsistencies or slight warping that caused shifts in the displayed number on the calipers, so I obtained this number as somewhat of an eyeballed average.

With these numbers, I was able to draft a box using the makercase website.

I chose the recommended dimension of 4x4x4 in³, using a finger size of 0.585 in because it was the smallest size option above the recommended 0.5 in that gave me around-equally spaced fingers on each face. I entered (what I thought was) the kerf, and downloaded the SVG file into Adobe Illustrator, where I added my name, class, semester, and the Will Rice Logo. Assuming the six faces were fine, I sent two faces to be printed on the Epilog Fusion M2 laser cutter, so if any mistakes were present, I didn’t waste six faces of 4×4 in material (foreshadowing).

• vector cut: 38 speed, 100 power, 10 frequency, 4 cycles
• raster engrave: 100 speed, 100 power, 600 dpi

spot the error!!

Here was the output. Do you see the problem? Turns out I inputted 0.034 in. instead of 0.0034 in. as the kerf, giving me two faces that could never join. Good thing I didn’t cut out all six faces I suppose. Lesson learned, check input parameters and Adobe Illustrator closely. I changed the kerf to 0.0034 in. and tried again:

next 2 faces cut

This time, the pieces fit together, hooray! Though in this case, the kerf might’ve been too small 🙁 The pieces could hold each other together with friction, but I felt it was a tad loose. Thankfully I only cut two faces again, I thought, as I switched the kerf to 0.005 in as an educated guess, after remeasuring the kerf box. I cut two more test faces and they finally fit how I wanted them to, giving me the greenlight to cut the remaining 4.

m2 laser cutting final 4 faces

I spent around the next twenty minutes putting together the box, starting by hand and being forced to eventually use a rubber mallet to press each finger together.

I spent a lot of time hammering each finger with the mallet, over and over and over, to make the edges as seamless as possible. This caused a small chip in the edges of one of the faces

chipped edge

This ruined the experience of running my fingers along each edge. I simply mustn’t’ve allowed it. Looking at the homework description, I felt using glue to fix it wouldn’t break any rules, since I wasn’t using it to “connect the sides” in any way. So I did what I must.

righting my wrongs

~170 in² of 3/16 in plywood (assuming ~$0.07638 per square in from Amazon): $12.99

Labor (4 hours at $10/hr): $40

= $52.99, excluding costs of equipment ($48.10 when excluding 64in² of wasted material)

Lastly of course, I cleaned my workspaces after usage.