Lego Shaped Lego Box

The Idea
With several avid Lego builders in the house and an ever growing collection we needed a better way to store our growing supply of bricks and pieces. After a bit of brainstorming and taking inspiration from the small tubs that one of our Duplo sets came in the boys thought it would be cool if all our Lego could live inside a 'Giant Lego' - very meta for the kindergarten crowd!!

Step 1: The Tools

The Tools
In addition to my small basement shop I'm a member in the local makerspace. The Columbus Idea Foundry has a ShopBot CNC Router and a 60W Laser cutter in addition to a complete wood shop with the usual compliment of stationary, hand and power tools. Given all the small circles and material being used I decided to fab the parts on the laser. The Mini 24 has a max size for the 12" x 24" which was more than enough for the largest piece. The only other tools used were a flush cut pull saw and a sanding station.

It might seem a bit backwards material selection was first on my list. I think in a project like this since it helps to prevent surprises down the road. The material needed to be tough, durable and easy to work with and take a kid friendly finish. A quick trip to Woodwerks and I've got a sheet each of 1/4" and 3/8" Baltic Birch plywood, 1/8" and 1/4" hardwood dowels and a fresh bottle of glue.

The imperial dimensions of the plywood are approximate, actual dimensions are metric so 1/4" is nominal 6mm and the 3/8" is nominal 9mm. Actual measured thicknesses are: 5.96mm & 8.94 respectively.

First step on the laser is to determine accurate settings for the finger and mortise joints. The kerf of the laser is small but needs to be accounted for in the design to have proper clearance for a good glue joint. A couple quick test pieces finds 0.23" is correct for the 6mm ply and 0.35" for the 9mm.

Step 2: The Design

We wanted our big Lego bins to be to scale and as faithful a reproduction as possible. For the overall form we chose the iconic 2x4 block.

After a measurement or two with the calipers it occurred to me that I can't be the first person to need the dimensions of a brick. 30 seconds of Googling confirmed my hunch and supplied all the dimensions needed for the project.

My methodology for the CAD files was to create a model using the Googled dimensions and then scale up to build size after the fact.
For the joinery of the main box elements I went with basic finger joints for the corners and a series of through tenons for the bottom.
The nubs on the top of the brick and the mating rings on the bottom would be built up of slices. Dowels would be used to align the slices and accurately locate them on the base and lid.

First up was a quick 3 view scale reference drawing followed by determining final scale.

The final scale ended up being determined by another classic Lego piece - the standard 32x32 Building Plate(Item 620). At 10 1/16" square I can glue 2 to the underside of the lid. Working backwards from that dimension will determine the rest of the

The nubs would be constructed from 3 @ 9mm and 1 @ 6mm disc. Total actual thickness is 32.84. Similarly the bottom rings were made from 3 @ 9mm rings. Total actual thickness of 26.84mm

The files I used for the laser are included here in CDR, DXF and SVG format.

Step 3: The Parts

The bottom of the box, the lid alignment piece and the top disc of the nubs are made of 1/4" plywood and the rest is 3/8". I considered making the whole box from 1/4" but seeing my kids climb and stand on every box, tub or container we have I decided to go the beefier route.

At this point determine the combined thickness of the nubs and lid pieces. Add 1" to this length and cut 8 lengths from the 1/4" dowel.
Do the same with the rings and bottom plate. Add 1" and cut 9 lengths from the 1/8" dowel.

Step 4: The Build - Inventory and Prep

The Build
This is really the easiest part - if you've been careful in your measurements things should go smoothly.
The first step is critical for the end product - sanding!
Sand everything now before any assembly. Both sides of all plywood pieces and vacuum the surface.

You should have the following parts:
24 - Nub discs (9mm)
8 - Nub caps (6mm)
8 - 1/4" dowels
9 - Rings (9mm)
9 - 1/8" dowels
2 - Ends (9mm)
2 - Sides (9mm)
1 - Lid (9mm)
1 - Lid Alignment Rectangle (6mm)
1 - Bottom (6mm)

Step 5: The Build - Nubs and Rings

Rings:
Build the three bottom rings by taking 3 rings and gluing them together using the 1/8" dowels for alignment.
The dowels should stick out about 1/8" on one side and 1" on the other.
Clamp and set aside while the glue sets.
Using a flush cut saw trim the short end of the dowel.


Nubs
Build the 8 nubs by gluing 3 9mm and 1 6mm disc using a 1/4" dowel for alignment.

Step 6: The Build - Bottom

Glue the three set of rings to the base using the dowels to align them.
After the glue sets use the saw to trim the dowels flush

Step 7: The Build - Lid

Glue the 8 nubs to the lid using the 1/4" dowel to align.
Clamp and let the glue set.
Use the flush cut saw trim the dowels.

Step 8: The Build - Final Assembly

After the base is complete the sides can be glued together. You'll need some big clamps or alternately a roll of painters tape. Wrap the tape around the box holding the sides together. Wipe up as much of the glue squeeze out as possible - especially on the inside corners as these are harder to clean up after the glue sets.

Step 9: The Finish - Tweak and Paint

After assembly is complete it's time to do a last bit of fine tuning before painting. After sanding and breaking all the sharp edges the only tweak I needed was a bit more clearance on the lid alignment piece to allow for paint.

Step 10: The Wrap-Up

A couple coats of some shiny red pain and we're done!

I did an alternate piece for the top layer of the nubs using the 3D engraving option on the Epilog. Not enough time for this build but I will incorporate it into the next one.