I've wanted to learn Solidworks for a while now. Obviously not going to be a total power user anytime soon, but I wanted to know enough to be mildly dangerous. I'm about to rebuild my Volkswagen's engine and while doing the teardown last semester I discovered that the engine stand I bought is just too big to fit the engine on. It's geometrically impossible to align the fingers with the holes on the back of the engine case. Even if I could, the fingers are large tubes that would dig into the flange on the back of the engine. I want to make something to adapt the two. My friend is helping me along the way, but I would like to do the final design.

Solidworks is provided to Georgia Tech students for free. A slightly painful install later and things were up and running. I was actually pleasantly surprised to find the included tutorials. I walked through the first four or five and made the various items they had to model. I found the constraint system to be really intuitive coming from Cocoa/UIKit's autolayout system, things made pretty good sense. The tutorials also were in a really natural order. You learn extrusions and extruded cuts first, which helps teach the sketch tools. With these you build a simple little box using the shell tool and finish things up with the fillet tool. The first tutorial also teaches how to make assemblies.

The next part teaches drafts and mirroring to make a little knob, it also introduces some more complicated uses of the fillet tool. The candle holder introduces revolving and sweeping. The hammer head introduces lofting. The torch (I think?) tutorial shows how to use equations to drive the sketch, the number of cutouts can be changed using an equation in the equation editor.

After walking through some of the tutorials to get comfortable I wanted a bit of challenge, so I looked around on my desk for something simple I could replicate. I have this little Bose speaker and I thought it would be a good challenge. I didn't get all the way through it, but I managed to replicate the base and the rubber feet before deciding I needed to get onto a real project. I really should finish it in the future, I think the stem would prove a good challenge with it's interesting angles.

My girlfriend and I are celebrating our one year anniversary, so I wanted to make her something kind of special. I had this idea of placing her first initial, V, inside my first initial, M. The ambitious part of me wanted to make some sort of necklace with a V-shaped hole in the M, with a small PIC that controlled a few RGB LEDs. The circuitry was pretty simplistic, the only novel idea I had was using two microcontrollers in a master/slave configuration. A PIC16 dealt with the four button inputs and controlling the five LED enable lines. A secondary 8-pin PIC12 connected via SPI did the PWM to control each LED's brightness. There was probably a better way, but our anniversary was quick approaching, and haste makes waste they say.

The battery was mildly tricky, I was planning on powering it from a small triple A or coin cell in the clasp behind the neck. The chain would actually carry some small current down to two pads on the top left and top right of the board. The idea was that just connecting the chain in the back would complete the circuit and turn the necklace off and on.

Routing is where this all fell apart. Even on four layers I just couldn't get the shape of the M and the V to be very pleasing and also have enough room to route everything down the remaining board area. Eagle was a pain here, the time it takes to import something from Illustrator (where creating desirable shapes is a somewhat pleasant experience) into Eagle and get the scale right is a huge barrier. Importing bitmaps is easier, since the ULP creates this solid shape out of lots of skinny polygons, but it's more painful when you actually want to import a shape to use as the boundaries of a polygon. Keep in mind here that the necklace was only going to be about 1.5x1.5 inches. Probably too small a goal for a two week project.

plan b

I had been looking for an excuse to learn how to use the water jet in Georgia Tech's Invention Studio, and my friend had some spare aluminum sheet he wasn't using, so I figured I could adapt the shape and still make a nice memento. I drew up the design in Illustrator, having a little more fun with making the letters pleasing, since I didn't have to worry too much about the board material or the capabilities of OSHPark. After the drawing was done it was quick work to get it carried over into the OMAX's software as a DXF. The machine in the shop can cut through inches of steel and granite so it didn't have too much trouble with the quarter inch aluminum plate.

I put a lot of elbow grease into polishing it. I think the aluminum I used wasn't very high quality, so I kept hitting little pores that needed more sanding. I started with really rough sandpaper and gradually worked up to some stuff I got at the auto parts store intended for wet sanding. After wet sanding I got tired of ripping my fingers to shreds so I bought a drill-mount polishing wheel. I tried various types of silver/metal polish until I found something that worked relatively well.

Looks pretty nice on the desk too. Kinda bummed it doesn't light up, but I think she likes it and I had lots of fun making it.

It's done! I took one weekend to finish the sanding. I finished working down the large inconsistencies in the surface with a rasp and a hand plane, then an 80 grit belt. I checked occasionally with a straightedge across the depth of the table to find any large dips.

Ideally, one would use a large planer to flatten the surface. I considered gluing the desk in multiple pieces, which I could pass through the planer individually, and then glue the pieces together. However, I think if the sides of the pieces were not perfectly perpendicular to the surface, the resulting surface of the desk would be slanted, just in sections. An alternative method would be to use a router jig that held the router at a constant height above the surface that the desk was resting on, that allowed for the router to be slid back and forth on the surface with some sort of fly-cutting bit. I didn't consider this at the time, but I believe that it would have been even more time consuming than the method I used, through may have resuled in a better result.

After the surface was sufficiently flat (a measure of which was highly influenced by how dusty my mask was and my level of fatigue), I switched to an 120 grit belt, then a 220 grit belt, just to smooth the surface. Finally, I worked up to 500 grit in a few steps on the random orbital sander. The last thing I did was cut the ends of the desk with a circular saw and a guide.

I decided to go with a satin polyurethane, and no stain. I briefly considered a black stain, but decided the color of the wood was too beautiful to mask. To make sure the finish was as perfect as possible, I took extra time to pretreat the surface as per the directions on the can. I completed the sanding with super-fine (~1000 grit) sandpaper. Since all of the advice I had seen for polyurethane included some note about applying the finish in a separate room to ensure no dust settled on the drying surface, I decided to leave the air filtering system running for a week before I applied the finish.

The next weekend I first applied a coat sanding sealer, which I let dry before sanding lightly with 500 grit sandpaper, just to knock off the fibers that had raised above the surface. After sanding, I wiped the surface down with a dry paper towel to take any dust off the surface.

I then applied multiple coats of polyurethane using a fine brush and even strokes (following the directions on the can). After each coat, I let the finish dry, sanded lightly, removed the dust, and applied another coat. I applied three coats total.

I wanted the desk to be portable, so I decided to go against legs that were secured to the surface itself. Ikea had some really cheap, simplistic looking trestle style legs that I decided to go with, which you can find here. I think they were ~15 dollars a piece.

I also snagged a second desk top. There's a campus buy/sell page for Georgia Tech, and I found someone selling a dining table for 20 dollars, with four chairs. We already had a dining table for the apartment, but needed the chairs, so I decided to repurpose the table as a side desk. I removed the legs, and the framing around the rim of the surface, sanded it down aggressively, and then followed the same procedure for the other desk, except I decided to use the stain.

The finish on both surfaces was great. I don't think I've ever had such a good result applying finish. I'm really excited about how everything turned out.

I've also posted more images on the DIY subreddit. Some of the comments are pretty great, and I've responded to some questions that people have had. Overall, the project was worthwhile. I had a lot of fun throughout the process, and now I have something I can call my own.