Introduction: Nutcase [for Loose Screws]
It's a nutcase.. for loose screws (made by a nutcase with loose screws). And yes, I know that not all of those are screws in the picture, but please don't bolt.
In any case, the fasten-ating idea has been floating around in my head after another incident of someone groaning at my puns. I happened to be holding fasteners at that time so I replied, "I swear I'm not nuts!" At this point, the person started to walk away while shaking his head, so I had to follow up with "Hey, don't bolt" (Not my fault; he walked right into that one...).
This nutcase essentially consists of stacked aluminum hexagons making up the walls of the box. The lid and sides of the box are decorated with my leftover nut collection from previous projects (mixed with random brass nuts from a hardware shop for color and surrounded by a rim of Keps nuts with free-spinning washers). Also featured are my loose screws (and bolts): besides the mental ones, I have lots of leftover screws and bolts from gear trains, watches, and woodworking.
I'll admit: the major factor that limits accessibility for this project is access to metal cutting equipment: I have access to a waterjet at my university, but I recognize that most people don't. That being said, there are alternative resources for cutting metal: more details in the next step.
Side note: if you like this tutorial, votes in the box contest would be appreciated!
Step 1: Materials
All files for laser cutting and waterjetting are in the zip folder attached to this step.
- 1/8" thick sheet metal (about 1/2 square foot; I used 6061 aluminum instead of steels for a lighter weight)
- 1/4" thick sheet metal (about 1/2 square foot; again, I used 6061 aluminum)
- access to a water jet machine, or metal cutting equipment (jigsaw...)
- Alternatively, you can outsource the machining elsewhere: caveat is that most places are pretty expensive for cutting only a few "small" pieces. Even so, this and this look like decent places that don't have as strict of a minimum order.
- Another alternative is to cut everything out of wood and spray paint a metallic coating to achieve the same general idea
- I made a wooden prototype via laser cutter, so the files for that were made in Adobe Illustrator (any similar graphical design software like Corel Draw and Inkscape, which is free, would work on most laser cutters too). I understand that many don't have this luxury, and this step isn't incredibly necessary, but I included it in the tutorial for completion of my prototyping process.
- I used an OMAX waterjet, so accompanying software were OMAX Layout and Make to format .dxf files for the machine, and Solidworks for generating the .dxf file (though other CAD softwares like AutoCAD or Pro/E would work too. Illustrator can generate .dxf files too, but I sometimes run into problem bringing them into other softwares because it's usually harder to clean unnecessary points and curves.)
Step 2: Designing and Prototyping
I wanted to model up the box so that I could get a visual sense of what the dimensions would look like. That meant using a CAD (computer aided design) software to set adjustable parameters (hexagon width, layer thickness, number of layers, etc.) until I ended up with something I found aesthetically pleasing. The picture below shows a model in CATIA, which is what I had access to on my lunch break, but free alternatives like Autodesk Fusion 360 work great as well.
Once I found dimensions that I liked on the computer screen, I still wanted something more tangible to get a physical sense of the overall box. To do that, I designed hexagonal cutouts in Adobe Illustrator for quick wood cuts on a laser cutter. With physical building blocks in my hand, I could better describe how many stacked layers I wanted of 1/4" thick vs. 1/8" thick material.
Step 3: Waterjet: Designing and Saving
I happened to have access to a waterjet so the next few steps outline what I did for anyone else with the same access. Otherwise, go back to my Materials step to see some alternatives I suggested.
The waterjet required .dxf files so I drew them up in Solidworks (SW and .dxf files are in the zip file under the Materials step). I used:
- 2x solid hexagon cutouts, 1/8" thick
- 4x nut shapes with pockets on the edges, 1/4" thick
- 4x nut shapes without pockets on the edges, 1/8" thick (acted as spacers between the 1/4" thick nut shapes)
- 1x "gear shape" for the lid, 1/8" thick
(Note: I could have used one of the spare circle cutouts and glued it to one of the solid hexagon for the lid, but I didn't want that full contact of a full circle whenever I closed the lid. With the "gear" design, there are only eighth small points of contact when the lid interfaces with the cavity so you won't get the unpleasant grinding noise from a full circle fitting into a pocket. That was the reason for the rough gear shape; I didn't have time to design a better looking gear, but at least there's only point tangency instead of a full circle. Hopefully that made sense!)
Click through the pictures attached above for step-by-step instructions in the notes on how to isolate .dxf files from a Solidworks part file.
Step 4: OMAX Layout: Cleaning the .dxf and Creating Paths
Once you have the .dxf, you need to import it into OMAX Layout to clean up extraneous points or curves and generate cut paths for the waterjet.
Click through the pictures attached above for step-by-step instructions in the notes on doing that, in addition to where to position your tabs, etc..
Step 5: OMAX Layout: Duplicating Paths and Saving
Once you generate one set of paths, duplicate them so you don't need to manually adjust your x-y position of the waterjet every time you want to cut the same shape. Then save and export a file for OMAX Make, the software that directly interfaces with the waterjet.
Again, click through the pictures attached above for step-by-step instructions on how to do those things.
Step 6: Filing and Polishing
Once all those steps in OMAX Layout are completed, send files over to OMAX Make for cutting on the waterjet!
Gently wiggle the cutouts back and forth until the tabs break from fatigue.
Grip the remnants of the tabs in the cutouts with pliers and wiggle back and forth to fatigue them off too.
Debur the edges with a demurring tool (or angle a file along the edges).
Use Scotch Brite pads (or the green side of classic green-and-yellow dish sponges) to buff up the aluminum and clean up the surface (in the picture below, the one on the left has been polished; random dings and scratches are much more noticeable in the unpolished hexagon on the right). Simply hold the pad firmly on a table and draw circles on it with the metal cutouts.
The shapes with cutouts or irregular geometry get caught easily on the Scotch Brite pads. To avoid that, work along the piece's edges instead of drawing circles with the entire piece. Hold the piece as shown in the picture below and sweep the edge of the piece in a semicircular arc (outlined in red), rotating every so often to polish the entire face.
Use files and Scotch Brite to clean up stumps from the tabs (in the picture below, the one on the left hasn't been finished yet, while the one on the right illustrates a finished surface).
For the nut shapes with little pockets cut out on the side: I also used files to slightly chamfer the sharp edges of those pockets, just so they wouldn't poke out as much.
Step 7: Assembly
Grab the cutouts and your adhesive of choice: time to glue up the layers! (note: do this in a well ventilated location for your health and sanity)
Sort your cutout shapes and play around with how you want to stack them BEFORE you permanently glue them together. I alternated 1/8" thick and 1/4" thick layers so that the little pockets in the 1/4" ones wouldn't overlap as much. I also slightly staggered the edges of the hexagons so that they didn't directly overlap with one another. In hindsight I wish I hadn't staggered them as severely as I did, as it made the overall hexagon shape less noticeable.
For the lid, I used one of the 1/8" cutouts to properly center the "gear" shape as shown in the picture below.
Step 8: Going Nuts
Spread out your nuts so that you can see all of them clearly. Then grab your glue and go, well, nuts while decorating the exterior of the box and lid.
I wanted to put a pile of different nuts on the lid as a handle to lift the lid, but it used more nuts than I thought. I was running out of unique nuts so rather than expanding that pile, I added a rim of 4-40 Keps nuts. I was careful with gluing them so that the toothed washer could still spin.
I also added some extra nuts on the underside of the lid and smaller ones in the pockets on the sides of the box (only 4-40 or smaller would fit in the 1/4"x1/4" pockets).
Let the glue set for ~10 minutes before using a q-tip to clean off the white powdery residue from dried super glue. (Fun fact: that "frosting" comes from a process called chlorosis: the vapor form of a monomer byproduct from the adhesive's curing process reacts with moisture in the air and settles around the bonded area)
Step 9: Reflections
And there you have it: a nutcase for your loose screws!
Things to change for the future:
- With more time, a nicer gear shape with involute teeth would have looked nicer on the underside of the lid instead of my rough gear shape.
- The nuts decorating the side looked too sparsely placed in contrast to the nut-filled lid. To balance that out, I would've liked more pockets on the sides of the hexagon so I could've encrusted more nuts.
- I liked the pile of nuts decorating the lid, but I was running out of unique nuts toward the end because it took more nuts than I thought to cover the ~9 square inches of surface area. I would've preferred to shrink the overall box size down to around a 2" wide hexagon if it meant that I could cover the entire lid with a pile of nuts...
At least those minor details don't drive me nuts... In any case, enjoy! As always, feel free to leave questions/comments/critique in comments below.