GEK Wiki / Chippers, chunkers, loppers, splitters, shredders, disintegrators, etc
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Chippers, chunkers, loppers, splitters, shredders, disintegrators, etc

Page history last edited by jim mason 8 years, 6 months ago

return to Practical Engineering


Here's our index of machines relevant for preparing gasifier fuels.  Please add more that you find.   The below is all the options "other" than spending $50,000 on a Laimet spiral screw chipper



Shears: circle, cylinder and spiral varieties


APL / GEK 55gal drum top shear proposal

55gal drum top circle shear chunker 


Inside circle shear firewood processors


Self-feeding spiral cylinder shear


Wayne Keith's truck axle cylinder shear


Jussi Äystö cylinder shear 


Ed Burton's Spiral Shear



USDA Teardrop Chunker



Rotary Blade Choppers


Rojek chunker from Czeck Republic


Jenson Chopper via Rolf Uhle



Manual wheel guillitine


Urban TR10 firewood chunker






Indian gang saw with feeder video


Wood Chippers


Wood chippers come in two main types: drum chippers and disk chippers.  Drum chippers tend to make a long curved slice.  Disk chippers make a more square chunk.  Disk chippers are highly preferred to drum chippers for gasification purposes.  Even with a disk chipper the fuel is not a thick symmetrical chunk as ideal, but it can be made to work.  The fuel still needs to be screened/sorted after chipping to remove the fines and too large pieces.


Greg Manning in Canada has built the most impressive DIY wood chipper and sorter i've seen to date.  Here's his photoset on the woodgas forum which shows the set up.


Greg's set up is based on the common low cost chinese disk chipper, and a rotating mesh cylinder to size separate the resulting chips.  These chinese disk chippers are available for around $1500-2000 new and are commonly driven off tractor pto's or 20hp and above engines.  These are the smallest disk chippers that will produce a reasonable fuel.  The common garden scale disk chippers, like the Troybuilt chippers, do not produce a chip of adequate size.  It is more of a shredded wood.


the low cost disk chippers are usually called 4" or 5" chippers.  here's one example  See other examples below.



Commercial Wood Chippers of Interest


Wallenstein BX42 Wood Chipper


Starchi chippers with embedded screening.  Directed at gasifier use


DR Power:


Mack Kissic:




Log Splitters


Redneck Axe Wheel Hand Remover


Cone splitters


Small disk splitters from Sweedish Volvo Gasifier





V-8 Chain saw



Analysis of Wood Chipper Chips, Particle Size Distribution, Moisture Content, etc:


Comments (2)

Jay Martin said

at 6:02 am on Dec 4, 2009

I think another effective option may be a grinder that is very similar to the Muffin Monster grinder. This grinder has counter rotating disks that will chunk wood (or just about anything else) with a relatively low input power requirement. Here is one video to demonstrate its operation.

Andrew Schofield said

at 2:22 pm on Jan 13, 2011

Jussi Aysto's chunker was the first of this type I have seen.
I wanted to use a machine that was very nimble in the forest.
Here is my shaft-driven version:

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