This idea started when I found this small oil lamp in our landlords storage shed. I have been working on bikes for a while now and I remembered that I had this old incandescent bullet light knocking around. This thing was pretty useless; it wasn't very bright and the batteries were not held in place very well, making the light cut in and out as you rode. I had been thinking about doing an LED conversion on it because I liked the style of the light so much, but the idea just seemed a little boring. Enter the bike lantern.
Note: I apologize for any confusion it may cause, but you will notice work being done on two different versions of this. The first was with the found pewter lamp and the second is with the brass one ordered from the internet. I have them mixed in the steps but the brass one is the final product that I have used for three months now.
*Actually I would still keep the commercial light as the candle-power of this project is pretty easy to quantify; It's one. Also check your local laws for bike regulations. We get pulled over pretty regularly here in Berkeley for light violations and I have yet to get a ticket, although I can't wait to see what happens when I do get pulled over!
Step 1: Materials
A mini Lantern either homemade or store bought. The closest thing I could find to the 5" pewter version I originally used for this project can be purchased here http://www.vermontlanterns.com/content/wedding-lantern-brass-mini-5 (this is the model you see used in the final version).
Something to house and affix your lantern to your bike. I used the steel housing from an old bullet light because it already had the mounting bracket for a bike and it looks cool. These can be found with a quick Google search however I think it might look equally cool if someone made their own housing out of a soup can or similar for that "Mad-Max" dystopian feel. If you do decide to order a bullet light pay close attention to the dimensions as these come in a number of sizes and it is crucial that the flame has some space to breathe. My light measures about 4"x 5". Also, it should go without saying that plastic lenses would be a bad idea.
Lamp oil. You can get super pure paraffin oil at most hardware stores or craft shops. While it may not be the brightest burning, it produces less smoke than a dirtier fuel like kerosene and is less likely to combust... I assume.
Drill and Dremel
Step 2: Sizing and Disassembly
Now that we know how the light will ride once attached to the bicycle, it is time to install the lantern. To do this we need to first clear out any unnecessary or flammable parts such as plastic switches and battery contacts from inside the housing. I went ahead and pulled out the reflector as well to be used in a later step. Also, on this particular light I was able to reuse the brass clip that held the reflector in place by bending it from a concave shape into a convex shape to hold the glass in place with out using any flammable glues. I imagine dots of "JB Weld" or "Quicksteel" may serve well in lieu of such a clip. You may want to go ahead and mount the lantern to your bike now before marking the hole for the fount. Hold the fount under the housing so that it will both ride level and will also take advantage of the maximum height within the housing. Trace the neck of the fount onto the base of the light and drill out the hole before fine tuning the shape with a Dremel sanding tool.
Step 3: Installing the Lantern
Light it up! On your first light the flame will almost certainly be choked out by lack of oxygen. Now you can take the lamp out and play around with how to best vent your lantern for maximum light without risking the flame blowing out from the wind whipping by. I started with a ring of holes around the base of the fount hole for air to be sucked into the housing. you should also put some pretty substantial holes on top to vent heat and smoke. After you're keeping a pretty good flame going you can reposition your reflector back into the light if it happens to be metal. I had to saw mine down with a cutting wheel to get it in the position I needed it in.
Eventually I had the right number of holes to keep the light lit while the bike was stationary. As you ride the light gets brighter due to the air that blows past the vents and fuels the fire.
Step 4: Extra Tweaks
To do this I used vice grips to hold the arm while I twisted off the wheel on the arm. You can then pass the wick-adjustment arm through a hole near the base, screw on the fount, then replace the wheel. This has been extremely convenient for the use of this light.
I also went ahead and used the cutting wheel to chop off the bits of metal that normally hold the glass chimney as well as shortening the metal tube that feeds up the wick to allow for more head-room for the flame. (Notice that most of these tweaks were done on version two using the nicer brass lamp from Vermont Lanterns.)
Step 5: Mount Up and Ride
Notes: After finishing my lantern I decided to see if there were any commercially available versions out there and found a whole slew of turn-of-the-century examples of bicycle lanterns HERE and on ebay. To my surprise they look remarkably similar to the one we just built. Apparently there were over 100 patents handed out for bike lanterns pre-1900, so check it out and crib some ideas, there are some really cool ones out there. Good luck!