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3D Printing: Top Assembly

Step 1: Fit Screws in Holes

Now, we need to prep the top part before we join the two halves together. First, make sure the screws pass through the holes without requiring screwing. You will notice that the screws will not go all the way down due to the head widening. Well, we're about to fix that.

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To insure a perfect fit, we will be heating each screw with a soldering iron, and gently pushing it down into the plastic, until the screw top is flush with the plastic. I initially tried to print the screw head taper into the top, but due to the micro nature of my printing setup, it created more of a mess. There are also several variations of screw head tapers, so you could purchase different ones, and use this technique for a consistent custom fit.

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This technique can ruin the part! Make sure no parts of the soldering iron touch plastic and do not push the screw through the hole!

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After you have finished this, your top should look similar to the image below. You will also want to use a knife to trim off any plastic that has raised above the surface of the top. You may have to repeat these steps 2 - 3 times, especially if you are being delicate (which you absolutely should be)

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Now that you have the top almost complete, lets put the top and bottom parts together (leave out the logic frame for now) gently screw it together. You may have to wiggle the top part a bit. Do not tighten 1 at a time all the way. Screw in each screw slightly. This will insure a more centered fit. Line up the top as precisely as you can. You will very likely notice some bowing of the plastic top north and south of the screen window. It's hard to see in this picture, but it is bowing about a mm down. We do not want that. This is due to slight alignment offsets in the screw holes.

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Step 2: Fine Tune Screw Alignment

Let's break out the soldering iron again. place the tip of the iron in the center of each screw and pull it slowly towards the outside of the watch. This will heat up the screw, and let it mold the plastic around it, allowing you to adjust the screw holes to prevent any top warping. You may need to repeat this several times, each time letting it cool.

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Do this very gently, and do not heat the screw for extended periods of time. Metal conducts heat well and this can melt all parts connected to screws!

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Once you have completed this, you should be able to place the logic frame inside, and re-assemble the OSWatch case with results similar to this.

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The four holes on the side of the shell are for the 4 input buttons. They are approximately 6mm X 6mm. You will need to add a 1mm notch for each of the 4 buttons on the top part. I did not add these to the stl file as it increases printing time, and if you are using the spacer part, you do not want these notches here, but in the spacer.

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Step 3: Attach Lower Programming Dock

Once it is assembled you will want to glue on the dock part to the assembled bottom base on the north side. Align this with the protrusion on the top lid as best as possible. I had the dock part as a separate file to enable the spacer part to be used as needed.

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Below is a Black watch build better illustrating the dock placement.

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Now you have the shell properly assembled and ready to focus on the asthetics.

About DoNothingBox

DoNothingBox LLC founded in 2013 by Jonathan Cook as a base to launch his passions, and showcase his portfolio. It's also to entity that holds any copyrights.

Updated May 16, 2014

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