Need to build a V8 wood chipper / shredder

Hi all,

Here is the basic idea…

I live in tropical Mexico, surrounded by jungle. One of the reasons I got into charcoal gasification was because of my interest and fascination with biochar. Jungle soils are not the rich, black soils you might think they are. In fact, they are deplete of nearly all humus, and biochar makes the most sense because it doesn’t break down.

Hence, I will be making charcoal for two purposes…

It just so happens that wood chippers and shredders are almost a foreign concept here. You can only buy them in the big cities, and they are 50%+ more expensive than they would be in the USA.

I need to build one… I need to build one with a big engine to make it act like an industrial shredder that can crank out a LOT of material. I don’t need a chunker because my gasifier runs on very small pieces of charcoal. Otherwise, I would build something like what Wayne built (which is a beautiful thing).

Additionally, I will be starting up a composting company to service local farmers with compost and mulch… Another reason for the small chips / shreds.

Does anybody have any thoughts on what mechanism might give me what I want? I’ve looked at a few examples from the Yahoo group, but don’t see anything that tickles my fancy…

I’m thinking a V8 without a lot of hassle… I saw what Chris ran into, and I don’t want to get too complicated here.

Thoughts? Examples? videos?

The goal is to find an old truck engine and hire a local welder to help me fabrication of a custom chipper / shredder.

Thanks guys!

1 Like

Hi Troy, Glad to see you dodged the hurricane! I’ve been working on biochar for the soil and charcoal for engine fuel for several years now. The need to “feed” the soil is something more and more farmers are starting to realize and glad to see you will be offering a service in this area. As far as making wood, branches and bark into mulch is something I’ve been working on. Chippers are common around here, but noisy and do not handle smaller pieces of material such as bark. I’m making a small rotary grinder and have high hopes that it will work well. For what it is worth, here is a video of a smaller unit.
I had my cutting discs made from 1/2" plate steel, cut on a plasma cutter. Putting it together will be a winter project. If and when I get it done, and if it works, I’ll post some pictures.
Until later, Gary in PA


Forgive the dumb question, but isn’t it easier to char the wood whole, then grind it up as charcoal?


Excellent! I’ve seen this before, and even called this company at one point… Looking forward to see your progress, Gary.

1 Like

Yep, no question… However, not all the wood with end as charcoal, as I will be making a lot more compost than charcoal.

Last year, we developed a double barrel retort capable of making char out of chips or pellets by inserting a hollow tube in the middle, thus eliminating the insulation effect of pyrolyzing small feed. So, it makes the most sense for me to chip/shred wood and then determine if it goes to compost, to the retort, or to the hammermill…

What’s even more cool is that I have a big cast-iron meat grinder that my Dad used for chumming up fish. I ran charcoal through it and it worked perfectly for biochar-sized pieces. I plan on slapping a motor on it and adding a hopper for the stuff destined to go in the ground.


Troy, Here is a larger version that really chunks the wood. Maybe you can build something along these lines!!
Chris, there is a need for mulch and charcoal in improving soil health, The mulch eventually decomposes away while the charcoal is retained in the soil, Mulch is used for weed and moisture control while the charcoal (biochar) is used for nutrient retention, soil aeation, water infiltration and inceased soil tilth,


All these wood shredding technology which is the least energy?
The idea is very sure of produir biochar (mulch, compost) to improve the soil or the energy.But produir CO2 emitting a minimum!
The tools knives seem better to me than a hammer.

Good morning Troy.

Just a thought but if you had a wood powered tractor for the power source there are a lot of implements that can be attached to the pto. Chippers , grinders, hammer mills , generators, water pumps and the list goes on.


Holy Moly! That thing is a beast…

Hi Wayne,

I would love to buy a tractor, but the problem is financial. I don’t have much money, and was thinking that I could probably find an old truck for about $1,000 and then maybe spend another $1-$2K over time on the fabrication of the shredding mechanism.

Otherwise–and at some point in the future when I’m more stable–I’ll need a tractor anyway for the future farm (still looking). PTO is definitely he way to go if the funds exist.


1 Like

Around here in Indiana, you can get an older tractor with PTO for a reasonable price, and most of the transmission and gearbox troubles have been worked out for you. Spend your time making mulch instead of re-engineering your power train.

1 Like

Well, I just looked online, and prices have gone up. Maybe I should invest in old farm equipment!

Hi Troy,

While I get the whole money issue, this is not a project I would like to see you undertake. There is just too much that can go wrong with high energy flywheels like those in a chipper. I would strongly suggest that you just save up money until you can afford a used Vermeer. I doubt it would be that much more expensive even after the freight. There are a lot of shafts and clutches and drive belts which will drive the cost up. At the end of the project you will have a mutt that you still can not get parts for. Sorry to be a party pooper.


1 Like

Hi troy, like the guys that been thinking this out for more years than us, it might be easy’er too buy old broke chipper shredder and then rebuild it, Building a bigger than usual shredder would be interesting too see. if reperpose parts were available, used steel should be going back down sooner or later. It would be neat too have at least a skid size shredder machine, Home made is the only way too build a big shredder without suit cases of cash, dont get caught with more than 10.000 cash or your money can be taken as drug money from lawless enforcement. GOOD LUCK,

1 Like

Troy I totally vote for the tractor/ PTO options. If you just need the engine and PTO there should be units with bad rubber, rotted rims, broken front ends dying for repurposing and made for the work… My Ferguson was running perfectly when I bought it and cost $800. She’s only 28hp but still. I also tend to agree with chris that you should char then grind much less energy intensive. But hey, your business model. Best of luck with the build.


Ok, after considerable thought and warning from various folks, I’ve decided to wait on the big unit… Not sure if I will attempt to build my own in the future, or save up for an older unit…


I am going to build a mini-shedder like the one Gary is talking about, and like the one seen here:

It looks like it would be a fun project, within budget, and useful for more than just shredding wood… This same guy has a string of video from concept to completion on the mini-shredder.

Also, with a small set of teeth like this little unit, the power source can be considerably less than something like the Muffin Monster… True that you’d get more done with a bigger unit, but you also need more power…

I’ll probably buy an electric motor and use a v-belt, or gear reduction if I can find it down here.

I’ll keep you all posted on my progress, and will share CAD files for anyone else interested.

Watch those fingers!

1 Like

Here is another unit that more closely resembles what I have in mind:

1 Like

And there is Jean Pain

Try feeding your chips into a hammer mill.


Have you thought about a machine such as this?

Although it will be more labour intensive, in your area that wouldn’t be such a problem. A machine such as this also allows use of young, otherwise low value material. Build should be quite simple, power requirements rather low. I could imagine a motor powered by wood gas driving such a unit.

For reducing large amounts of heavy timber into good quality chips, I agree with using a pto driven machine. Valmet, or a similar Swedish manufacturer makes such a unit, appears to be very high quality.


Troy, I spent 10 years driving around Mexico and know the place pretty well. If you buy something here, they will really charge you heavily at secundaria. It might even double the price. Tractors in Mexico are real expensive. You are better to start out wth a truck. They are much more common. The common engines are Perkins, Detroit and Cummins. I’ve worked on chippers for many years and know them very well. The higher the horsepower, the wider the blades. You can use 12 inch blades with a gasoline 6 cyl. It’s just slower. You must have a blower if you are going to have much of a discharge chute. I have a chipper flywheel here and it weighs about 300 lbs. It was mated to a 361 CID Ford. It also had a 200 lb drum. The newer chippersd are auto-feed that restricts the feed speed. The older, more dangerous chippers fed at whatever rate the drum and knives could pull in. They sell for cheaper here.

If I were going to make a chipper in mexico, I would start out with a truck. I would weld the spider gears to lock the axle. I would cut open one pair of the duals and fill them with concrete. I would bolt the u-joint to the differential with 1/4 bolts so that they would shear if something jammed. I would run it in low gear to keep speed down and just depend on flywheel weight to do the cuting.
The second problem is holding the knives. The old chippers used 12 in to 16 in diameter drums and fairly high speed. The new chippers use a bigger diameter drum and lower speed. I would definitely go with a bigger diameter drum and lower speed. The old knives were clamp-in but, the newer knives are bolt in and much easier to mount.
It’s all do-able if you have a good engineering sense and a good welder.