Wood Chunker Design Elements

I get lots of questions about wood processing and the simple truth is there is more than one way to skin this cat depending on:

  • What parts you have available
  • Your budget
  • Your wood inputs


So I put together this chart with the elements of a wood chunker that should help you to start planning your chunker project.


  1. Power- If you have a tractor I would start there. Next I would consider a dirty old used engine. Something that is cheap and ideal for practicing woodgas will be fine for chunking wood. 4 cylinder is probably ideal, but v-8’s work too.
  2. Gear reduction- This is just a means of slowing the shaft speed down to something usable like 60-100 rpm at the cut head. Ebay has lots of deals on gear boxes or you can use old wheels of differing sizes pressed together to reduce the speed.
  3. Energy storage- A smaller motor will be able to do more work with a flywheel because of duty cycle. When you aren’t chunking wood the energy is banked up in the wheels mass, just waiting to be harnessed.
  4. A cutting head should slice and pinch the wood so it comes apart in neat chunks. The screw head is complicated, so I would go with an old tire rim cut to a steep angle and sharpened.


I hope that helps. Thanks for reading.


  1. JT May 20, 2016
    • Ben Peterson May 20, 2016
  2. Rufi July 21, 2016
    • Ben Peterson July 24, 2016

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