Charcoal crusher / grinder update

I am starting a new thread for the charcoal crusher I made almost a year ago and the updates I’m making to it. Originally, it was wooden and meant to explore the concept.


It follows the principle of rock crushers and the diagram shows how it functions.


It worked, but being wooden it was starting to degrade. Some screws were working loose and it did not work well on hard charcoal from a retort.

I rebuilt the crusher with steel jaws.

The steel teeth are sharper and can crack the charcoal easier. I also made a few other changes.

I added a 5kg flywheel to the eccentric shaft and mounted the motor better. A funnel was added to the top for easier loading. I also increased the angle on the output screen to allow the charcoal to exit the machine better.

The motor was always under powered for the machine. The moving steel jaw is much heavier than the wooden jaw and the motor just doesn’t have the power to move it and crush the charcoal. I was hoping the flywheel would help compensate, but the motor is just too weak at 1/6 hp. I really need at least a 1/2 hp motor, or even better a 3/4 hp. I will have to try and source one somewhere.

Meanwhile, here’s a video of me babying it. Loading any faster just chokes the motor.

I think a new motor will just about finish this project. I could make the frame metal, but it doesn’t seem necessary at this time. The one thing I can foresee changing is making the bearing surface of the jaw bracket on the eccentric much wider. With the heavier jaw and more power from a future motor, the wear will probably increase on the eccentric shaft. I will have to monitor it closely.


I knew I was saving a collection of 3/4 hp washing machine motors for a project… I made a manual crusher with this concept, but with only a hinge at the bottom of the one jaw. It completely lacked teeth, but still worked pretty good. Now I have some ideas.


I’m just wondering, do the teeth/jaws have a function for the quality of the charcoal (i.e. less fines/more uniform sizes) or is it for use of less power to grind?
Or is there other reasons or the teeth?


I’m convinced that teeth reduce the crushing action and therefore produce less dust. I went with sharp teeth and low rpm (100 rpm) to limit dust.

The staggered teeth reduce power demand and also allow any particles that are already small enough to pass without additional crushing.

Throughput is over a hundred gallons an hour.


That is a very solid build Chuck , mine goes even slower and still makes dust but not so much , i like the idea of it coming out underneath into a box if you were to put the door on you could then use a vacuum cleaner to suck the dust out maybe .



Johan, I think the teeth provide more of a cracking like action. It’s like taking a piece of charcoal and snapping it in half with your fingers rather than crushing it under foot.


I am sure you are right. Is there any reason the ‘ramp’ or chute doesn’t go over the top of the centerline of the shaft? Where your chute ends, the teeth are going up at that point. Seemingly it would be more of a crushing action then the cutting action on that side. But you may have found a reason for doing it that way.


Thank you Chuck, Dave and Martin.
I like that analogy Martin, very obvious when you put it that way :smiley:


I envy you Dan. Back in the States you could always find a dead washing machine along the road, big old machines with 3/4hp motors. I have found only two in 4 years of looking here. The largest motor being a 1/5 hp. :slightly_frowning_face:


Treadmills have a nice sized motor: 1.5HP or so. A lot of treadmills are bought in January (New Years Resolutions and all). I’m not sure when they get thrown away though… later?


Hey Sean, I set it up with the hopper extending behind the rising teeth to maximize the possibility of the pieces that are already small enough passing through un-cut. A significant amount of material falls behind the toothed drum and on through. The larger pieces are just kind of shoved around by the rising teeth until its their turn on the anvil side.


You can’t find them anymore. People are opting for delivery and installation, and they haul the old one away for free at the same time.


I think this is where they are getting smashed. If you are interesting in trying to improve it, you might try to slow the speed down in half or put a temp chute on with a small screen or gap that still allows small stuff to drop through. Otherwise, it looks like it works well. :slight_smile:


The next generation crusher is done. I didn’t have a higher horsepower motor handy, but I did have another small one. So it got added to give about 1/3 horsepower between the two:

It still didn’t give the power needed. And as I expected, the eccentric shaft was starting to wear badly due to the heavier jaw:

So I installed two pillow blocks I had bought anticipating this need last year:

The wear on the shaft was indicative of a lot of power being wasted through friction. Now the motors have enough power to run the machine. Partly they are helped by making the eccentric less aggressive.

I think this is the final version. Unless the wooden frame shakes itself apart, I won’t make it out of metal. I do need to make a better fitting biochar collector under the screen. Wheels on the machine would also be nice in order to move it about. But I am very happy with the throughput and quality of the charcoal. Oh, if I find a higher power motor, I will use that instead of the two I have now.


Well i think you should be well pleased with that crusher Marty , it seems to be fast enough getting it down to the size you need and the dust content did not look so bad at all , must have been hardwood i guess .
Keep your eyes open for a geared 12/24 volt motor from a wheel chair /invalid scooter that’s what i have and have great torque and you can even run them direct off solar panels when you have direct sunlight or with battery in the mix , it Might be a bit slower than the motors you have running now though .


Thanks Dave. The charcoal was from hard woods although nothing like oak or maple.

It’s hard to find anything in Chile, but I will keep my eyes open for a scooter motor. A slower motor like 400 rpm would be fine. I had to slow the 1490 rpm motors I had with an extremely small pulley on the motor shaft.


It looks great! I would add a brace or two to the backside where the char is coming out if you are worried about shaking apart.


Probably the nicest crusher on the site. Wery litle dust! Excelent.


Thank you Kristijan, that’s very kind of you to say.