The awesomeness of the NES Cartridge Clock must be spread all across the lands.
Now, you could go online and buy one... BUT:
1) We all know making your own is more fun than being a consumer whore
2) They take the easy way out and just drill a hole through the whole thing. Less elegant. You'll see.
3) They have limited game selection. Let's face it, Elevator Action just has no demand.
4) This way, you can support your local mom 'n' pop hobby store and/or yard sale.
Let's DO it.
Step 1: Hunting/Gathering Supplies
(1x) Nintendo Entertainment System Game Cartridge of Choice
(1x) Clock Innards*
(1x) AA Battery
(?x) Spray Paints**
(1x) Drop-cloth, newspaper, painting surface, etc.
(2x) Smidges of Tacky Glue
*available inside most (all?) clocks or your local hobby store (Michael's et. al. if necessary). If you don't have a "12" of your own, you'll need one of those too.
**you will need as many colors as you want for the hands and/or numbers.
1) Tiny Screwdriver*
2) Power Drill & 5/16" Bit
3) Hot Knife**
4) Inky Pen
5) Needle Nose Pliers (preferable)***
*most likely flathead
**a rotary cutter would probably be preferable over the drill/hot knife combination. I just don't have one...
***you will need to tighten the clock components, so the smaller your grabby-grippy device is, the better.
Step 2: Prepare the Clockworks
Follow the instructions on your particular paint. They usually tell you to spray a few thin layers on, leaving two minutes or so between each layer. I found it worked very well to spray the hands, shake the can, spray the numbers, shake the can, spray the other numbers, shake can, etc. There was no down time and it turned out very nice-like. Again, don't forget to flip them and paint the other side.
As an alternative, you can hang each part from a thin thread or wire through one (or both) of the holes. This will allow you to paint both sides without flipping, but can also lead to problems because the parts are very light-weight and the spray paint will tend to blow them around.
I chose to paint four of the clock stuffs red and one clock stuffs metallic black.
Step 3: Disassemble the Cartridge
Open the cartridge and remove the electronic(s). Make a note of which way it's facing. You'll have to put it back the same or it won't shut. Well... I don't really know if it won't shut, because I never tried it. Just do it right.
Step 4: Prepare the Front of the Cartridge
First, it would behoove you to find a suitable workplace with proper ventillation. You will either be making some nasty plastic dust, or some death-fumes.
Take the front half and make two lines on the inside. The first line is directly down from the center of the cartridge's pull-tab area. The second line is directly horizontal with the little plastic support nub about halfway down.
Drill or create a 5/16" hole at the intersection of these two lines. If you don't want to be extremely accurate, make sure you err towards the bottom and away from the side. Vertical placement is much less important than horizontal... if you want the clock to line up in the textured area on the front. Be careful when drilling. Due to the thickness of the material, the drill bit will try to grab it (most likely). Stay in control and don't rush it. Clamps help immensely.
Now that you have a hole, you can insert the clock mechanism and find out that it won't fit. We'll have to cut out three things:
1) Remove the center screw mount. Completely. You might only need to take out half of it to fit the clock, but it's easier just to lop the whole thing off.
2) Remove the lower support boss.
3) Remove the tiny plastic pin directly below the cartridge pull-tab. Depending on your hole placement, you may not need to do this.
Unlike real surgical procedures, your boss-ectomies have no need for perfection. The resulting surface does not need to be flush because the clock has a little rubber pad that will hold it off of the surface slightly anyway.
Remove the washer and two nuts from the clock shaft and install the mechanism into the front of the cartridge. The mechanism and rubber washer should be behind the plastic and the washer and large nut should be in front of the plastic. Set aside the small round nut for now. It will be the final piece assembled on the completed clock. Check to make sure everything fits and then remove the clock mechanism. This may seem silly, but it'll save you time if you make sure it fits now.
The front (easy) half of the clock is now complete.
Step 5: Prepare the Back of the Cartridge
To make sure the gaping hole in the back of the cartridge matches the small one we made in the front, we'll use a little bit of trickery and a pen.
Reassemble the cartridge without the screws and electronics and drill a 5/16" hole down through the preexisting hole in the front and on through the back. This ensures that the holes are lined up.
Push the clock shaft into the hole from the backside of the cartridge (is it getting warmer in here?). Trace around the clock so that you know where to cut. The outline will most likely fall over the side onto the beveled edge of the cartridge slightly.
Cut the rounded square out of the back and remount the clock into the front of the cartridge. Try installing the back of the cartridge and check for clearance issues. Trim back the square hole until the back can fit easily onto the front without interference.
Step 6: Assemble the Time Machine
Remove the back, replace the electronics, replace the back and screw it on. Leave out the center screw. You should now have an NES game with a clock sticking out of it.
Cut a 1 and a 2 off of the number sheet, or find the numbers that you have elected to use. Apply a smidge of Tacky Glue to each and place within the pull-tab of the cartridge. If glue squishes out, don't worry, it will dry clear and unnoticeable. You can either let this dry before installing the hand, or (if you're impatient and just want a damn finished product already) you can be careful not to bump the numbers and put the hands on now.
Install the MINUTE hand first. This is the hand with the small hole that has two flat sides. It should have a little slop and only fits down over the silver threaded portion of the clock shaft. Rotate the hand so that it is pointing to the 12. Without rotating the hand or shaft, remove the minute hand.
Install the HOUR hand, pointing to the 12. The hour hand fits very snugly over the white (nylon?) portion of the clock shaft. If you want your clock to line up at 12, make sure this is correct.
Reinstall the MINUTE hand, verifying that it is pointing to the 12. Screw on the small nut over it to remove the slop and tighten with your needle nose pliers. I have found that tightening by hand tends to be too loose, causing the minute hand to be ahead on the way down and behind on the way up. This won't matter if you mount your clock horizontally, but who the hell does that.
With your hour and minute hand secure, press the second hand onto the pin in the center of the shaft. Depending on how much paint got in there, you may have to press quite firmly.
To set the clock, only move the minute hand, the hour hand will follow, and the second hand doesn't matter. If you attempt to move the hour hand you will screw up the allignment so that the hands don't line up at 12.
Pop in your favorite brand of AA batery and watch the magic happen.
Step 7: Your Competition
I also haven't provided instructions on how to mount the clock because I don't presume to know to what surface you plan to mount the clock. I used velcro on my first one because I wanted to stick it to my cubicle wall at work.
If you want to poke a hole or mount a hook on the back, follow my "How to Find the Center of Mass of a Roughly 2D Object" Instructable. **coming soon**