This is a replacement crank for these flashlights: http://www.harborfreight.com/pack-of-2-dynamo-led-flashlights-65207.html

I bought these during the "Halloween Nor'easter" back in 2011. I broke the crank on one about 3 days into our power outage. At the time I fixed it with "plastic welding" (I stuck a large flathead screwdriver into a fireplace, then jammed it into the busted handle and melted it back together. Proper safety precautions were taken, don't try this at home.) but I have the tool to fix it properly now.

Print both parts. Disassemble the flashlight. Replace the crank. Reassemble the flashlight (I've included a picture of the gears and shafts in their correct places). Screw the knob to the crank (I used a #4 x1/2 wood screw). Crank it up!