Sunday, November 22, 2015

Steamer Trunk Coffee Table (with Stealth Cutting Laser)

What beats a plain coffee table? A coffee table made from a steamer trunk. What beats coffee table made from a steamer trunk? A coffee table made from a steamer trunk that hides a liquid-cooled cutting laser inside, of course.

In brainstorming ideas for a permanent laser cutter home, I got stuck on the idea of building it into a table.
Steamer trunk with a hidden surprise
I looked online for ideas and really liked the look and hidden storage of "steamer trunk" coffee tables. The laser cutter was already quite large, however, so I wanted the trunk that didn't have a lot of extra wasted space. None of the existing tables I found came even remotely close, though, so my only option (fortunately) was to construct one from scratch.

Cutting angle iron
Most steamer trunk coffee tables I found were built to resemble a classic steamer trunk resting on some sort of stand, perhaps with shelving below for magazines and such.

I decided to make mine out of plywood and steel and give it a distressed industrial look. I bought about 50 pounds of angle iron from Big Orange to make the frame. To cut the steel to length and miter the ends, I used a portable bandsaw from Harbor Freight that I'd mounted on a small stand.

Sadly, my existing welding skills were pretty sucky, so the next step would be tricky. The project required a lot of welding, so I'd have to step my game up to get it done. Fortunately, it also offered ample opportunity to practice. At the beginning, my welds were a brittle, lumpy mess. After a couple of false starts and more redos than I would have liked, I finally figured out that by carefully cleaning the metal beforehand and keeping the wand close to the surface, I could get a reasonably clean bead.

Full welded frame
Welded base
With that knowledge in hand, I welded together the table frame, creating both the trunk and a base unit that would hold a rack for sheet materials and the water supply.

Adding straps
After the frame was fully assembled, I sprayed it with rust-colored red primer followed by an oil rubbed bronze paint. When it dried, I lightly sanded the edges to give it a faux weathered appearance.

To complete a steamer trunk look, the frame included steel simulated "leather" straps, which I sprayed a contrasting copper color.

Caster wheels
To give the table mobility, I found some nice cast iron caster wheels on Amazon, and painted them the same copper color as the straps.

I didn't want the hard wheels to scratch the floor of my Man Cave, however, so I printed polyurethane rubber treads for them on my 3D printer using Ninjaflex flexible filament.

Corner hardware
From the Rocker woodworking store, I got some very nice streamer trunk hardware to make everything truly authentic, including corners, latches, and hinges.

They really sell the illusion. A light dusting in copper paint helped them blend in.

Staining wood
Distressing plywood
For side panels, I used hardwood plywood, and recuited Little Monkey and Littler Monkey to distress them before staining. Their eyes lit up when I gave them hammers and told them they could let loose with them.

I attached the paneling to the frame with button head cap screws to mimic the look of rivets. The hinges, handle, and corner hardware were fastened the same way. With the addition of some wire shelving on the bottom, and some access holes in the bottom, the table was complete, ready for its new occupant.

Hinging top to base

Installing laser cutter
I modified the laser cutter internally to route exhaust fumes to the bottom of the unit instead of the back, and also added some switched outlets so the fan and water pump could be enabled from the main control panel.

I inserted the laser cutter carefully, routing each water hose and power line through its corresponding hole in the trunk button. It was an incredibly close fit, with less than 1/4" clearance all around. In fact, I had to order a special right angle power plug to replace the one that came with the unit, and even had to shave that to make it fit.

Cutting name plate
Finished nameplate
As a final touch, I used the laser cutter itself engrave a nameplate for its home.

Completed table with Engraver
With the trunk top open, the laser is ready for action in all its blazing glory.

Assembled table
But with the top closed afterwards, all one sees is a handsome piece of furniture with nobody the wiser.

Sunday, November 8, 2015

Frickin' Laser Beams

3D printers are awesome!  I love using mine to repair widgets and toys, and make whatever random objects come to mind.  However, I've sometimes come to find the technology limiting.  First, it's not really great at making finished goods.  Also, the build materials are primarily constrained to a few types of plastic.   Finally -- and perhaps most importantly -- it could really use the added sexy appeal of a destructive frickin' laser beam.

Frickin' Laser Beam
Makerspaces are often equipped with laser cutters (aka laser engravers), providing an excellent compliment to 3D printers. Capable of cutting or engraving shapes and images into wood and plastic, and even etch images into glass, the results look completely professional, as they use the same process (if not the same machines) as commercial manufacturers.

For a hobbyist, I've always assumed that astronomical prices would keep the purchase of a laser cutter permanently unaffordable, or at least spousally indefensible.  In the last few years, however, a number of low cost Chinese laser cutters have come onto the market.  Instead of $3500-$15,000 or more, these bargain units have literally decimated the entry-level cost barriers to the technology.  And while the software can be awful and the hardware relatively crude when compared to their larger brethren, these laser cutters can be surprisingly functional and excellent platforms for hacking, modding, and upgrading.

Unboxing my K40
The king of these low cost laser cutters is the K40, a generic name for a family of similar devices assembled from different Chinese manufacturers using the same or similar parts.

I discovered them while investigating sub-$200 mini engravers -- compact devices built around the laser diodes used in DVD burner drives -- units capable only of slowly burning patterns into small wood objects such as keychains and cell phone cases.  In doing my research, I was surprised to find out that for only a little more money, I could purchase a full size unit built around a real laser.  Instead of a laser diode, a K40 uses a water-cooled 40-watt CO2 laser tube, and is capable of not only engraving, but cutting through 1/8" thick acrylic, cardboard or plywood.

Direct from China, one can get a bare-bones K40 on Alibaba for as little as $300, but I chose to pay only slightly more on eBay to get one from a US-based distributor.   It arrived a few weeks later, packed in an abundance of foam and cardboard.  It was larger than I expected, but I found it a temporary resting place on some ottomans in the Monkey Man Cave.  I'd work later to build it a unique permanent home, which I'll detail in a future post.

The laser cutter came with a submersible aquarium pump to circulate the cooling water and a moderately janky exhaust hose and squirrel fan to remove the gases and smoke generated when engraving.  In a few minutes I was able to get up and running, placing the pump in a vat of distilled water and routing the exhaust hose out the door.  All I needed to do was fix a poorly-designed ground connection (paint doesn't conduct electricity folks!) and adjust the mirrors to get a properly aimed and focused beam.

I was half expecting to see a satisfying lightsaber-like beam, but sadly, a CO2 laser only produces invisible infrared light. It does have the capability of blinding its operator without advance warning, however, so I was sure to order a pair of CO2 rated laser glasses to wear when working with the cover open.

The weakest component in the system is the software.  The laser cutter only works with MoshiDraw, a program that runs under Windows and functions both as a driver and structured drawing program.  It's buggy and confusingly organized, and the English translation is absolutely atrocious.  However, the program is quite functional once you figure it out, and is capable of completing a wide range of projects.


As a warm-up exercise, I first tried making some test cuts in paper, essentially using the engraver as an oversized, overpowered Cricut, those computerized die cutting machines used by scrapbookers to make paper hearts and doilies and such...  except of course with the added satisfying (and may I add manly) power of a death ray laser beam.

To follow up, I tried my luck with plastic.  Using two-tone copper/black laminated acrylic sheet, I cut and engraved a replacement for the laser cutter's own control panel, which I had enhanced with a few extra switches and knobs.

Cutting acrylic laminate
Completed panel
Installed panel

I used a similar material to make bookmarks engraved with a MakerMonkey logo I drew in Photoshop.

Lastly, I tried the laser cutter on plywood, scorching the same logo into the surface, making this custom engraved coaster.
Laser Cutting Plywood

The possibilities are endless for future things to make, but the laser cutter couldn't stay in the middle of the room forever.

First, it needed a permanent home, and of course something ordinary just wouldn't do.