OSAT stands for Open Source Appropriate Technology and this tool is a clever solution to a age old human need for fire. Using your bare hands to spin a stick back and forth with enough force to create the friction needed for fire causes blisters and other wounds to form on the hands. Especially if the first attempt is unsuccessful. With this tool and a skilled user, many fires could be started much quicker and the user would have no blisters. The scad file can be customized for most sticks and rope can be hand woven from plant fiber. Picture of completed print coming soon. For now, on the right are screenshots of the 3D models and a Primitive Technology video where I got the idea from.
Momentum Fire Starter[edit | edit source]
Project developed by Cascheel. Here is a Link to a Primitive Technology YouTube video that shows the original design working and some other uses for the tool. The basic consept is that the fly wheel gets compression fitted on the straight-ish stick and the rope is attached to both ends of the pump with the middle of the rope also attached to the end of the stick. the pump gets pushed down and the momentum of the spinning stick re-wraps the rope around the stick for the next pump.
Bill of Materials[edit | edit source]
everything needed besides the 2 3D printed parts are essentially free. You will need:
- A straight-ish stick with a diameter between 10 and 20 mm
- About 2 feet of hand woven or manufactured rope depending on how long the stick is.
- Some dry kindling to catch the hot ash
- Another small peace of wood to drill onto
Here are the OpenSCAD files for the Momentum fire starter. They are easily customizable.
I couldn't upload the .stl files directly because of the following error
If you want the stl file for a 10mm diameter stick you can just open the .scad files and click the export to stl button. or you can get them from my YouMagine wich also has the same customizable SCAD files and the stl files.
Tools needed for fabrication of the Momentum Fire Starter[edit | edit source]
- MOST Delta RepRap or similar RepRap 3-D printer
- Knife or a sharp rock
- Optionally you could get a rope making jig as well but it is not needed
Skills and Knowledge Necessary to Make the Momentum Fire Starter[edit | edit source]
Technical Specifications and Assembly Instructions[edit | edit source]
- Print both the FlyWheel and the Hand Pump. Make sure that the optimal flat side it laying on the print bed
- I recommend a 90-100% infill for the flywheel but you could probably get away with only doing 70%
- Print will take between 1 and 3 hrs to print in total depending on infill and print speed
- After printing it will take almost no time to assemble
- Obtain the materials
- Start a hole in the drill wood and cut a triangular notch leading off the edge of the wood to allow hot ash to fall out
- Cut a notch into one end of the stick
- Compression fit the flywheel onto the stick until it is about 1/3 the way up the stick
- Feed the longer end of the stick through the center hole of the hand pump
- Put the middle of the rope into the notch and tie it off with another piece of rope or glue
- Tie the ends of the rope to the ends of the hand pump
- See video of assembly [Video]
Technique Notes[edit | edit source]
- find a way to steady the piece of wood that you are drilling on. this could be with a heavy object, your foot, or your other hand if you are skilled enough.
- Find the sweet spot between keeping pressure downward on the pump handle and allowing the rope to wrap around the stick.
- If you are having troubles, try shortening the stick or shortening the string to find the optimal string length to stick length that works best.
- make sure you cut notches in the drill wood for the ash to fall out of
- make sure your kindling is dry
Cost savings[edit | edit source]
- It will cost less than $4 of filament.
- saves the user from hand wounds
- Closest Commercial Equivalent is $22
- $18 savings