Intro: Voronoi Bento Tray
Made with cherry wood, this easy to make bento tray is the perfect addition to your next dinner party, or just for Netflix and snack. Using a router template bushing makes it easy to batch out multiple copies of the tray. I'll show you how to make the tray, and a quick primer on using a router template bushing kit too.
My wife and I like to take average ramen to the next level by adding a soft center egg and lots of other veggies. These trays are perfect to hold a variety of vegetables and toppings allowing people to load them up at the buffet with the veggies they like instead of dumping all the veggies on a cutting board, family style.
Here's our recipe for a perfect ramen bowl:
1 packet of your favorite ramen, cooked to package directions with 2 cups water. Add to a deep bowl.
1 egg, boiled for 6 minutes. Put in ice water immediately after boiling to stop cooking. This results in a soft yellow center. Peel and cut in half, immediately place in ramen bowl.
Then add any of the following:
carrots, cut into matchsticks
green onions, sliced
cabbage - either a standard round head cabbage, or Japanese cabbage, sliced
meat - any leftovers are good; I like rotisserie chickens, and leftover barbecue/smoked meats, sliced or shredded
Step 1: Prepare Router Template
Design a router template in your favorite CAD or vector graphics program. You will need to be able to print to scale. I used SketchUp, but I could not figure out how to print to scale, despite searching online thoroughly. Instead, I took a screenshot and printed using my printer's scaling until the measurements were correct. For a 1x6 board (5.5 inches wide) use 67% scaling on the screenshot image above.
Print out the template to scale, cut out, and use spray adhesive to affix the template to the plywood. I prefer 3M Super 77 adhesive, and I only apply the glue to the template in light strokes.
Cut out the template using a scroll saw, jig saw or similar. To access interior voids, drill a hole for the saw blade to fit through.
Remove the paper from the plywood template. If you can't remove all the paper bits from the template, use a heat gun or hair dryer to soften the glue and peel off the paper.
Sand and smooth all edges where the router will carve. Any inconsistencies will show up in the final project, so take some time to make a quality template. You can carve as many copies as you like later, so definitely take your time.
Note that I cut the gap between the top left and top center void in the template. The top center void was too small to be functional for a 1x6 board.
Step 2: Carving With a Router Template Bushing
Creating copies of the same project repeatably is easy using a router template bushing kit. The kit consists of an adapter to mount the bushing to your router base plate, and exchangeable bushings that lock or screw into the adapter. The bushing rides against the template above the workpiece, and the router bit plunges through the center of the bushing, carving into the workpiece below.
There are two types of bushings on the market:
Bosch - uses a quick release type plate with wings that lock into a spring loaded adapter. Used only in Bosch routers. Bosch also sells an adapter plate to mate with Porter Cable type router bushings also. This is the adapter pictured and used in this Instructable.
Porter Cable - uses a threaded bushing to screw into the adapter in the router base. Used by every other router manufacturer.
Both are great options. I use the Bosch adapter only because I have a Bosch router. If I had another brand, I'd use the Porter Cable style. I do like the quick release feature of the Bosch. I leave the adapter screwed into my plunge router base all the time, and only add a template bushing when I need it. It does not seem to be gummed up by sawdust. I blow out dust with compressed air after every use.
Typically these adapter kits don't sell with the router, it is an optional accessory.
You can also use them in purchased, non-DIY templates, such as lettering guides for signs and other templates.
The router bit needs to be able to plunge through the template and into the workpiece at your desired depth, but the router collet -- which holds the bit, can't hit or rub against the template. Therefore, you either need to chuck the bit towards the end of its shaft, or purchase a long reach bit for the purpose. Never chuck the bit without enough grip for the router to safely hold the bit. I have found my maximum depth with my bits to be about a half inch into the workpiece.
You also need to make sure the bushing and router base plate are centered. The bit should never carve into the bushing. An off center bushing is not only unsafe, but also could produce irregular results in the carving as it rides the template. If one side is proud and the other side is shallow, your carving isn't going to be uniform on each side of an inner void and will result in a sloppy look. To center the baseplate and template bushing, you can use a centering cone.
Step 3: Set Up Router & Carve Voids
Make sure the power is unplugged from the router. Before using power tools, make sure to wear the proper safety gear - hearing and eye protection.
Select the right size bushing for your bit. I am using a bullnose bit to carve the voids. This bit leaves lots of tool marks, and a bowl/tray carving bit would work better.
Install the bushing into the template adapter. Chuck the bit into the router leaving enough grip on the bit - at least an inch. Plunge the router down through the bushing and hand spin the bit (power unplugged!) to make sure it isn't carving into your bushing. Recenter the bushing if needed.
Invert the router and place on a flat table, onto the bushing. Plunge until the router bit is flush with the bushing. Zero set the guide rod on the router depth gauge. My router has a rotating turret with different depths, incremented by 1/8 inch. I mark the final depth with a tiny square of blue tape. Rotate the turret to the final depth, then put the router on the edge of the table so the bit can plunge below the bushing. Plunge the router all the way down and make sure the collet isn't rubbing or bumping into the template bushing or anything else. Once everything flight checks, retract the plunge to the top, rotate the turret back to zero and then rotate the turret 1 step down, 1/8 inch depth.
Place the router base over the void in the template, plug in the router, turn it on and plunge to the first 1/8 stop. Move the router around until all the material is carved away at 1/8 inch depth. Retract the plunge to the top, turn off the router, set the depth an 1/8 inch lower and repeat. Continue this process until the desired depth is reached.
When you have carved to the desired depth, zero set again and then repeat on the other voids in the template.
I opted to have 2 of my voids a full 1/2 inch deep, 1 void at 1/4 inch deep, and 1 void at 3/8 inch deep.
Pry off the template with a paint scraper or similar tool, taking care not to break it. Clean off any excess tape and remove excess adhesive bits with mineral spirits.
Label the template with a sharpie and store it someplace memorable for the next time you want to carve a Voronoi Bento Tray!
Step 4: Shaping and Sanding
Mark and cut off the top right corner, shown in the photos - the red marked line.
The other side has an angle tapered from the surface to 1/3 of the board thickness. This section is a place to put your thumb when carrying it, and a place to rest your chopsticks against the tray.
To make this taper, sand it down with a belt sander. First mark off the top edge with blue tape to prevent unwanted belt sander abrasion. Second mark the 1/3 thickness on the board. For a 3/4 inch board, the mark is 1/2 from the bottom or 1/4 from the top. Then holding a handheld belt sander at an angle above the workpiece, sand it, checking often to ensure you didn't sand past the mark on the edge. I matched the 2D angle from above holding the belt sander flat, then tilted the sander to the side to match the carving angle into the workpiece. I eyeballed the alignment and recorrected as I sanded. Then remove the tape.
Sand all of the edges smooth.
I also added a 1/8 inch round-over detail to the top with my router, then flipped the tray over and did a 45 degree chamfer to the bottom, covering 1/4 inch of the thickness.
Begin the long process of rough hand-sanding out the tool marks, then moving to finer and finer grit to smooth out each void. For the surfaces reachable by a power sander, use a detail or random orbit sander to smooth out any rough spots, moving to finer and finer grit.
Step 5: Finish With a Food Safe Coating
Use a rag to apply a food safe finish. I used food grade mineral oil. I applied 3 coats, allowing the tray to dry between coats, wiping off the excess and reapplying. Polish with a dry clean rag and allow to dry fully.
These trays work great as a personal veggie tray for dressing up ramen or pho. They make great sushi plates. They can be a fun conversation starter as a personal cheese plate or appetizer tray at dinner parties.