I recently saw this clock online. It's really cool, because you can turn it to rest on any of its twelve sides, and it displays the correct time for somewhere in the world- the city listed at the top. But I thought that the user interaction was unclear- do you turn the city you want to the top, or the bottom? It's got enough sides that you have to double check to make sure your city is right on top. And they're selling it for over a hundred dollars...
It's not really that useful if you're a world traveler- you have to take the minute hand off or it's wrong every time you turn it. But the hours are right, so it's good for if you're doing international business, or have friends overseas that you want to contact. Actually, I was considering making a version that left off the cities and simply displayed the names of my wide-spread family members so that we'd have an easier time discussing when to Skype call.
**a further disclaimer- some places don't do Daylight Savings, and even those that do differ by country on exactly when it occurs. So it's still not always right. But I still think it's cool.
Laser cutting done at TechShop!
Step 1: Materials
Step 2: Design
Here are my inkscape files. Pick one:
"WorldClockTextNotEditable": This one is ready to be exported to your file type of choice and cut out*. I used a city from each of the 24 time zones and stacked them- I like the juxtaposition of cities exactly twelve hours different (e.g. prague and honolulu).
"WorldClockEditableText": I have placed two offset dodecagons inside the original twelve-sided polygon to use as paths for the text. This means you can edit which cities are displayed- pick which ones are important to you! After you change the text, convert the text to a path and then delete the inset dodecagons so that the laser cutter won't cut them out. *Also, read the footnote.
*I have designed this for a .25" diameter inset cylinder for the clock gear post. It is also designed for 1/4" plywood, so if you change materials, make sure to change the size of the holes around the outside accordingly.
Step 3: Laser Cut It!
Step 4: Finishing Touches
You may want to sand off any scorch marks from the laser cutter.
I discovered that my clock gear box needed to be inset into the wood in order for the hands to turn, so I put the gear box on the back , traced it in pen, and used a Dremel router to make a little pocket for it.
Step 5: Glue in Clock Box
Put it all together! Your clock box should fit into the back nicely. Glue it on.
Remember to remove the minute hand- it won't be correct if you turn the clock!