This instructable started off as a bit of a prank that I thought I'd share, and is a bit off of the instructables I normally do. I've never been a fan of having clocks in the living room. To me it represents an area where being regularly reminded of the time is counter intuitive to the relaxation and rejuvenation the room was intended for. My wife, on the other hand is the type of personality that, I hesitate to say is bound by the time. Having her way I'd find a time piece in every corner of every room of the house, so when she adamantly demanded I install a clock in the living room, I had to oblige. This was my compromise.
I've built reverse clocks in the past and they are as simple as flipping over one part. The most difficult aspect is remembering how your gearing is positioned, however this is a hurdle that can be overcome by taking a few pictures along the way. You'd be surprised how easy it is to forget where something goes and having a photo record of the 'before' can go a long way to ensuring it goes back together the same way it came apart.
I'll be including a rar file with a usable clock face as part of the instructable, however feel free to use your own as you see fit. I'm also including a short vid so you can see the mod as it's being built.
Step 1: Tools And Supplies
Step 2: Disassembly
First you need to remove the clock face. On the cheaper dollar store clocks they should literally pop out. Next remove the hands from the clock and flip it over. On the back you should find a box that houses the gearing that should be held in by a couple of clips. Pry them open and the entire assembly will come out.
Step 3: Pulling Your Gears
Once you've removed your mechanism, lay it with it's back facing upward. We will be opening it to remove gears so it's best not to lay it on a flat surface as it will push all of the gearing out under it's weight. If you place it back on the clock face, with the spindles that move the hands protruding through the center hole that should prevent that from happening.
It's very important to keep a record of your gear placement so I suggest taking pictures during each step of disassembly. That way, should you forget the position of a particular gear you can easily use refer to your images.
The part you're looking for is the coil as identified in image #2, and more specifically the magnetic bar that passes through it. It should remove as one solid piece with a small pinion gear that drives the entire clock.
Step 4: Making The Mod
First pull your pinion gear. That should allow the entire coil to be removed from its housing. Once the coil is removed, you can pull the magnetic bar. The bar has one of its arms that passes through the coil and one outside of the coil, so pay close attention to its orientation.
Now what you need to do is to flip the magnetic bar over so that it's the other arm that passes through the coil. This will cause the reversal of the clock. You may need to modify the bar in order for it to fit properly into the housing. If one of the corners on the bend part of the bar is clipped, you'll need to clip the opposite corner. Simply take a pair of side cutters, or pliers with a cutting edge and snip it off. It doesn't need to be terribly neat, or accurate as long as it fits the housing.
Step 5: Reassembly
Now you need to put everything back the way you found it. Reinstall your coil assembly as well as all of your gears then close the cover. If you run into trouble, refer to your pictures...
Bet you wish you took them now huh?
Step 6: Testing
Before re-installation you should test your mechanism. Install the hands on your clock, all running the same direction then insert a battery. You second hand should start moving right away (hopefully in the wrong direction) and if you wait a few minutes, you should see your minute hand rotate. Now, if you're really patient, you can wait for the hour hand to change, however if both other hands are flowing normally, you can suppose that it'll work fine as well.
Don't install the mechanism just yet.
Step 7: Making A New Clock Face
You're probably not going to want to reuse the original clock face since well...it's wrong, so I suggest creating a new one. I've created a jpg of the one I designed for my clock and included it in a .rar file. Just print it out to the size you need, cut it out and glue it into place. You'll also need to cut, or punch out the center for the spindles to pass through.
Now, If you'd rather use your own you can have a bit of photoshop fun designing it. Get creative with it. Have your numbers going backwards, or even have the numbers mirrored so that they're backwards as well. Whatever you decide, you can personalize your clock any way you chose.
Just be sure that your new face is oriented properly on the clock. It'd be unfortunate if the 12 is off kilter to the wall mount...unless you want it that way of course. Really, who says that 12 needs to be at the top?
Step 8: Finished
Once your face is set into place reinstall your mechanism then position the hands. Snap the glass back on and hang it on the wall.
It's a great little hack and a fun way to prank people, if you're so inclined. Just have a good time making it.
As usual, I hope you enjoyed the instructable and thanks for following.