Portable Holes

An unexpected membership to Saint Louis' new maker-space, TechShop, led me to force myself to pursue new creative directions. I ended up creating a series of granite trinket boxes with 3D-printed and milled-aluminum lids. Images and details follow:

The boxes are approximately four inches square and 1.5 inches tall. They are made of counter-top quality granite or marble. The lids are approximately three inches in diameter. The 3D-printed lids are approximately 3/16 inch thick and are made of ferromagnetic polylactic acid (FePLA). This plastic-based material contains 40% iron, giving the lids a pleasant texture and considerably more heft than traditional 3D filament (with the added benefit that magnets stick to them). The aluminum lids are approximately 1/4 inch thick and are milled from high-quality aluminum plates. The horizontal patterning is due to the action of the 1/16 inch end mill removing material from the base. Although they appear textured, the lines are actually quite smooth. The inside of the boxes contain a 3D printed shell with a laser-cut acrylic disc bottom. This assembly is then secured to the bottom of the box using black silicone. The boxes are then elevated from the surface by clear rubber bumpers in each corner.

Because of my inordinate fascination with LEDs, I also made a series of the boxes using garden paver stones. This material is thicker than countertop granite (approximately 4 inches) and allows for room for circuitry that enables lights to shine with the lid is removed. On the bottom, the box has four microscrews that secure the battery (3-volt 20mm diameter Lithium).

The aluminum lids, on their own, make delightful paperweights. So I went ahead and milled some extra ones.

Unfortunately, milling the lids takes over an hour and a half. And there's not much to be done but just stand around and watch the machine do its work, monitoring for any problems. But even that seems fast compared to the 3D printing process. Each of those lids take well over two hours. But I really wanted a few more, so I made silicone molds and casted the lids out of resin (see my Tutorial on making "Individual Things" for details on the process).

And now some back story on how this project came to be...

Not all that long ago, I lost the job I had held for over twenty years. I originally thought that moving on to a new position would be much more stressful than it actually was (given how much I really don't relish change…). But I have to admit that in addition to some interesting new professional challenges, my new job has also lead to some unexpected benefits. I would have never guessed that one of these was an opportunity to engage in some new creative endeavors (via the rather circuitous route described below).

My new faculty position is within the College of Arts and Sciences. It just so happened that the Dean of A&S recently purchased memberships to St. Louis' new TechShop. He thought that it would be a great chance to involve students in the Cortex District on Forest Park. Fortunately, the Dean purchased enough memberships that he was also able to ask faculty and staff if they were interested. I ignored the first email that went out, thinking that there would be many folks clamoring for the opportunity. However, when the second email came out, I couldn't help but write back stating that if positions were still available, I'd welcome the chance to use a membership (for personal reasons, of course). Soon afterwards, I received an acknowledgement that I had a been approved for a three-month membership and a $250 class credit.

My membership began with a tour of the TechShop. It is an 18,000 square foot facility filled with a dizzying array of equipment. I was overwhelmed by the possibilities and didn't quite know where to begin. That, along with the fact that I was certain the Dean would want to see what I had created with my membership, created a sense of uneasiness. I felt I had to come up with a project idea quickly. I initially toyed around with doing work with their silk screen equipment, or perhaps their Arduino workbenches, or even their metal shop or woodworking area. These were all things I had done before and felt some comfort with. Eventually, I convinced myself that if I was going to really make the most of my membership, I should push myself to try some new things.

But before I could do anything, I had to take a number of "Safety and Basic Use" courses. This was somewhat frustrating, because I wanted to just jump right in and get creating (despite the fact that I still hadn't settled on a good idea just yet). But I understood the need for the place to insure their students weren't going to hurt themselves or damage the equipment. Although I was still somewhat unsure of what my project would be, I had always been interested in 3D printing, so that was the first course I took. It didn't take long after that before my idea began to coalesce.

3D printing in action

In order for me to successfully execute my plans, I next needed to learn how to use the WaterJet cutter. This room-sized machine uses a 55,000psi stream of water to cut through just about anything – they say it will slice through six inches of steel with no problem at all. When operating the machine, TechShop makes members wear a lanyard stating they were using a WaterJet cutter. This is in case there's a catastrophic injury and the user is rendered unconscious, attending doctors will know what treatment to pursue. I had always imagined that a cut from the machine wouldn't be that big a deal because, after all, it was just using water. But evidently, the pressure is so great, that a little nick on the finger would shoot contaminants far into the surrounding tissue, forcing an amputation at the wrist.

I found the WaterJet class a little intimidating, but with it behind me, I was convinced I would be able to do what I had planned for my new project.

For years, I have been fascinated with man hole covers. My thought was that I would make trinket boxes cut out of granite with 3D-printed man hole cover lids.

One of the things that surprised me the most about my time at TechShop was how friendly and helpful all the staff was. Although my project idea was well conceptualized, I did have tons of questions about how to actually execute it. Not once did any of the TechShop staff look askance when I explained my idea, but rather they worked with me to figure out what I needed to do to make it all work.

At this point, I needed to begin gathering materials for my project. Most 3D printer filament has a characteristically plastic like sheen. I searched the Internet and finally came up with a source that sold ferromagnetic filament - it's 60% plastic and 40% iron. Parts printed with this filament are heavier than with traditional filament, have a pleasant rough texture, and (most awesome of all) are attracted to magnets.

I took my favorite photos of man hole covers from Saint Louis, and imported them into Adobe Illustrator. I then traced the contours to create clean flat artwork. I exported the art to an .svg file that I then imported into Fusion 360. Although I had never used that program before, I found it to be fairly easy to use. With my artwork imported, I was able to create 3D elevations from the flat originals.

The 3D printing process is not complicated, but I did learn that it is not something that can be rushed. Although it would have been possible to crank out the lids in a matter of fifteen minutes or so, the results would have looked quite horrendous. So I had to learn to curb my impatience and allow for over two hours for each cover to print. And because I hadn't bought a full spool of filament, but rather just received a slightly tangled coil, I had to sit with the machine the entire time to make sure that the filament did not get jammed. Needless to say, I spent quite a few late nights after work printing.

In the meantime, I needed to begin the process of creating the actual boxes. I was surprised to find how many granite countertop vendors there are in Saint Louis. I wrote down the addresses of several that were close to home and went on a search. My hope was that I could find a store that would let me purchase a scrap or two. Much to my surprise, all three places I went to were more than accommodating. When I explained what I wanted to the guy at the counter of the first place I visited, he replied: "Over there. In the dumpster. Help yourself." Despite being in my work clothes, I hopped in, got covered with dust, and ended up with some very nice pieces.

Then, one night, I bundled all my scraps up and headed to TechShop. The WaterJet is the only machine that they charge members to use. Because of the garnet powder they mix into the water, along with the cost of water and electricity, it's not an inexpensive piece of equipment to run. There's no cost for all the necessary set-up, but once you hit "run" and the pump is engaged, a counter starts ticking. TechShop charges $3.00/per minute of cutting. The software in which cutting paths are created provides an estimate of cutting time - based on the quality of the cut and the type of material. So, going into the project, I knew I was going spend a considerable chunk of change on cutting alone. But because I saw this as probably the only time I'd ever have the opportunity to do this type of project, I resigned myself to the charges.

Because TechShop had opened fairly recently, it just so happened that I was to be the first person to ever try to use their WaterJet to cut granite. This caused considerable excitement, and a number of folks came to watch. I was a bit nervous about using the machine - both because of the aforementioned injury potential and because doing something wrong could result in damages to the nozzle (which would cost me $250 to replace).

For my first couple of cuts, the TechShop personnel (they call themselves "Dream Consultants") stood by to provide any assistance I might need. But before long, they saw I had the hang of things and let me run everything by myself. In the end, I spent from 8:00pm to nearly midnight using a $250,000 machine. I was exhausted, but thrilled with the results.

cutting granite on the WaterJet

Because the WaterJet can just cut straight through a piece (and not make layered cuts to specified depths), I ended up with pieces of granite that were shaped like square donuts. In order to turn these into "boxes," I ended up 3D-printing an insert. But because that process is so slow, I didn't take time to print the bottom. Instead, I took yet another class. I learned how to use the Laser Cutter to create a bottom for my box out of acrylic sheeting. I then secured the bottom and the 3D-printed shell into the granite using black silicone caulk. I designed the inner shell with a small cut-out portion so that when the lid sits on top, there's a place to press down to pop the lid off. This enabled the lid to sit flush with the top of the granite, yet still be easily removable.

Although this whole process was tremendously fun and resulted in some gorgeous pieces, there was yet one more step I wanted to take. I enrolled in the Tormach class so I could learn how to mill my man hole covers out of aluminum. Despite the fact that I thought that the WaterJet was intimidating, I found the Tormach even more so. There were so many steps and factors to control for. Because I had run out of class credit from my original membership from the University, I had to pay for the class myself. As I was attending the class, there were times I felt that I might have wasted all that money because there was no way I'd ever be able to successfully use the machine. This feeling was compounded by the fact that the instructor had never used a 3D modeling program to create toolpaths to control the machine.

I finally convinced myself that I wasn't going to wimp out and would do my best to actually figure out how to use the machine. I ended up typing out all the notes I had taken during class, supplementing them with additional information I found on the Internet. There were mathematical formulae to use in order to compute the "feeds and speeds" for the piece being milled. I also had to purchase special endmills that were small enough to render the designs I wanted to cut. That said, my original designs for the 3D printed lids were too detailed, so I had to simplify them to accommodate a 1/16 inch bit.

And just as I was the first person at the St. Louis TechShop to cut granite, I was also the first person there to successfully render a 3D modeled toolpath on the Tormach. And once again, the instructor was tremendously helpful - there when I needed assistance, but giving me the freedom to actually run the machine myself.

milling a manhole cover on the Tormach

My friend, Kelly, often talked about the fact that people who spend money on experiences are generally happier than people who spend the same amount of money on things. In the end, I think that the time and money I spent on this crazy project were well worth the new skills I've learned and memories I'll have.

And for what it's worth, here are the original photos on which my holes were based...