# DIY Jaw crusher



## aunboy

Hello, I'm building a chipmunk type jaw crusher. I have everything I need and I'm building it out of "stuff and things and whatnot". The jaws will be made out of built-up grader blade. Seems to me the angle of the jaws will be pretty important if it's to function as desired. I'm guessing that the angle should be about 22 degrees. Does that sound right? Anyone have a jaw crusher that they could measure the angle between their jaws? I tried looking on the web but came up empty.Thx.Andy


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## aunboy

Well, I'm not sure if there's any interest in this thread. I looked around the web for homemade jaw crushers and I didn't find anything so it looks like I'll be climbing this tree alone. I've decided that a 22 degree jaw angle is too obtuse so I brought it down to about 15 degrees. The crushing chamber is being made by welding 2 wide flange beams together at their flanges. My jaw is 30 inches long and that will give me an openning of about 7-3/4 inches by 6 inches so that's my capacity. Larger ores will have to be sledged/jackhammer down to this size. The jaw will be rocked by an eccentric camshaft that's powered by a 2 hp electric motor. Actually, the flywheels will store the energy of the motor and do the actual crushing. The jaws will be lined with removeable grader blade "teeth". You can see my general layout in the attached pix. Hope it works...
Andy


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## Militoy

aunboy said:


> Well, I'm not sure if there's any interest in this thread....



I wouldn't say there is no interest in the thread - I'd love to have a jaw crusher - but since I didn't have anything really helpful to add, I kept my peace, and stuck to lurking. Actually, I'd rather have the little Bobcat to restore - as opposed to breaking it down for crusher parts!


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## aunboy

Gasp! Break down my bobcat? Never! It's in the first picture because I had to use it to lift the flywheel that I'll be using for the crusher. It's 40 inches in diameter cast iron and weighs a pants lode.


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## Harold_V

Do continue posting your crusher as it develops. If nothing else, it will inspire those that feel a need for one themselves. 

I've slowly come to understand that posts such as yours often go without response, but many benefit from them. You never know who is reading, and who may be looking for the precise information you provide. 

Harold


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## Oz

I agree! But by all means post more details as there may be no one here that has built a crusher, but there are many with expertise in different disciplines that will lend a hand or opinion if they see a flaw. One example would be your choice of grader blade teeth. A great material for what you have in mind, had you chosen differently I am sure you would have heard from Harold as he is not just a refiner but a machinist as well.

I particularly like that you are using a flywheel. Mass with inertia is great for overcoming peak loads, but be warned that all that stored energy can also turn your assembly into a pretzel if it is not sturdy enough.


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## Harold_V

Oz said:


> I agree! But by all means post more details as there may be no one here that has built a crusher, but there are many with expertise in different disciplines that will lend a hand or opinion if they see a flaw. One example would be your choice of grader blade teeth. A great material for what you have in mind, had you chosen differently I am sure you would have heard from Harold as he is not just a refiner but a machinist as well.


I'm inclined to think that's a good choice. Manganese steel is typically used for high abrasion applications, so that may be what he has. If not, it may be a medium carbon steel. That may not be the best choice, but unless the crusher is used on a continual basis, I expect it will serve adequately. 

I admire anyone that has enough skill and courage to build their own equipment. I purchased nothing in the way of refining accessories aside from my three burner hotplate, gas fired, and the blower for the hood, which was modified to meet my specs and demands. I built everything else. I know of no other means to obtain items that are tailored to one's needs (at least for refining). 

Harold


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## aunboy

I'm trying to strike a balance here and use up some of the scrap I have without spending too much. I have a piece of austenitic manganese but it's about 4 ft X 4ft X 4 IN thick. It's actually the jaw out of a real (big) ore crusher. The grader blade is easy to find for free (the county snow plows and graders gave it away when it needs replacing), is high carbon yet reasonable enough to work with common shop tools. That's why I feel the need to make the teeth replaceable as they will wear down. The other option would be to make the teeth removeable so they could be refaced by welding them up with stainless steel rod (or some other hard alloy). You often see this done on bulldozer or loader blades/buckets. 
Thx.Andy


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## Claudie

aunboy said:


> Well, I'm not sure if there's any interest in this thread. I looked around the web for homemade jaw crushers and I didn't find anything so it looks like I'll be climbing this tree alone. I've decided that a 22 degree jaw angle is too obtuse so I brought it down to about 15 degrees. The crushing chamber is being made by welding 2 wide flange beams together at their flanges. My jaw is 30 inches long and that will give me an openning of about 7-3/4 inches by 6 inches so that's my capacity. Larger ores will have to be sledged/jackhammer down to this size. The jaw will be rocked by an eccentric camshaft that's powered by a 2 hp electric motor. Actually, the flywheels will store the energy of the motor and do the actual crushing. The jaws will be lined with removeable grader blade "teeth". You can see my general layout in the attached pix. Hope it works...
> Andy



We're watching.... :|


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## aunboy

For those unfamiliar with how a chimpmunk type of crusher works, it's pretty simple. There are 2 jaws. One is stationary (like the top teeth in your skull) and the other jaw rocks to provide the crushing action (like your bottom jaw). I'm working on the rocking jaw now. The piece of steel I selected from the scrap pile is 5 IN wide by 1 IN thick and 36IN long. It has built up ends that are 3 inches thick. One one end, I'll be welding a hinge pin to provide a pivot point for the jaw. The other end will ride on the eccentric shaft and provide the rocking motion.I'll weld stiffeners to the back of the jaw to ensure rigidity.


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## Palladium

I love playing in the scrap yard. Give me a tourch and a stick welder.  
I to am interested in what you are doing. I just don't have anything to add at this time. Google will index this thread for all on the net to learn from, so somebody out there in the future will benefit from it.


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## shaftsinkerawc

One thing to keep in mind when building your unit is to make it as easy as possible to clean up between different batches of ore. If used for a single site then not as important but you will still get heavies that trap behind the joints of the blade and everywhere else. I'm also watching with interest. awc


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## sawmill

Auboy

I have been following your thread too.
I notice that you said hinge. Aren't you going
to use an adjustable toggle,for regulating the
size of the output? Also are you using a roller
cam,crankshaft with bearing,or pitman arm
to move the jaw ? How much stroke are you
going to use on the movable jaw?

The jaw angle should be set so it will only
open just a little more than the biggest rock
that you intend to crush at the top.
Determining the correct angle is mostly a
trial and error thing. Too much angle will
cause it to not feed well ,because it will
force the material up . Too small of an angle
will cause it to jam. Cross hatch the jaws with
hardface all the way to the top,so they get
a good grip. You may not want to put any rocks
into orbit. :roll:

Google small rock crusher,there is several old
patents with drawings,and specs.


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## aunboy

I have been following your thread too.
I notice that you said hinge. Aren't you going
to use an adjustable toggle,for regulating the
size of the output? 

No. I know that chipmunks and probably others use this feature but I want this to be as absolutely simple as possible with as few moving parts as I can conjure. A simple hinge knuckle welded to the jaw tangentially that will accomodate a 2-1/2 IN DIA hinge pin will be the pivot point. I'm shooting for a 1/8 IN exit slot. After that, the material goes into the ball mill (an old cement mixer w/ trailer balls and sledgehammer heads acting as mill balls). So the real question becomes: Is it possible to take a 6IN DIA cobble sized piece of ore and reduce it to 1/8IN in one pass? I don't know but I'll soon find out. I don't care how long it takes but I am concerned about jamming. I have a jackhammer and I can reduce ore before I feed it in but I also have a blown disc in my back and I'd prefer to limit my time on the hammer. 


Also are you using a roller
cam,crankshaft with bearing,or pitman arm
to move the jaw ? How much stroke are you
going to use on the movable jaw?

Friction cam, no roller, similar in principle to an auto cam/valve train. This will wear down of course and need to be refaced from time to time. Not sure about the stroke. My first guess is about 1/2IN eccentricty on a 2-1/2IN Dia shaft (major axis 3IN, minor axis 2-1/2). Looking at around 300 rpm on the shaft for about 5 cycles per second (!! seems like a lot??) Big flywheels. 

set so it will only
open just a little more than the biggest rock
that you intend to crush at the top.
Determining the correct angle is mostly a
trial and error thing. Too much angle will
cause it to not feed well ,because it will
force the material up . Too small of an angle
will cause it to jam. 

I'm worried about this. I'm guessing about 15 degrees but since my angle isn't adjustable, I'll be married to it once everything is welded up. But then again, it doesn't have to work well. It just has to work... 

Cross hatch the jaws with
hardface all the way to the top,so they get
a good grip. You may not want to put any rocks
into orbit. 

Yes, I was planning on stainless rod for that (which I already have). Hope that's a good choice...

Thx.Andy

Google small rock crusher,there is several old
patents with drawings,and specs.Top Report this postReply with quote


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## Militoy

aunboy said:


> Gasp! Break down my bobcat? Never! It's in the first picture because I had to use it to lift the flywheel that I'll be using for the crusher. It's 40 inches in diameter cast iron and weighs a pants lode.


 
Still lurking - Your crusher thread caught my eye since I play around with raw ore on a regular basis. Your Bobcat caught my eye - as my only tractor is an early 41 Farmall BN with a PTO and drawbar, but no hydraulics or 3-point. I'll be lurking along - and sucking up any free knowledge I can pick up as your thread progresses. It seems that your thread caught a bit of interest from the board after all!


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## sawmill

aunboy

I don't know that stainless rod would be a good
choice for a ore crusher. How are you going to
separate the stainless bits that wear from the
jaws,from your crushed ore? Wouldn't the 
stainless cause problems ,with the other
processes? I don't know ,and am just asking.

1/8th on the first pass ,with stationary jaws
may be asking a little too much too. Even so
a rod mill will handle a bigger grind,and is real
simple to build. The rod mill would also grind
to leach,or smelt classification size.

I believe you are pretty close with the stroke
and jaw angle. If your ore has lots of quartz
it will crush pretty easy.


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## skippy

You may be able to add adjustment fairly easily by having the pivot point being eccentriclly located with a round rotatable bearing block.


This picture has what I am talking about, on a roller mill instead but it should work on a jaw crusher


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## aunboy

Quick update. I'm still working on this but I have to burn thru some 3 inch thick steel so I had to order a number 4 tip for my oxy-acetylene torch. Waiting for it to arrive so I can get back to work....


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## aunboy

Well. My first set of cutting tips were stolen by the post office employees in Denver so I had to buy them twice but at least I can get back to this project now. Here's a close up of the bottom of the jaw where it's connected to the hinge pin. The pin is 2-1/2 IN solid round stock. The knuckle is a 2-1/2 section of well casing. The jaw will be welded to the knuckle and will pivot around the pin. So the bottom of the jaw seen in this pix will travel an arc as the other end of the jaw rides on the eccentric shaft. A small arc but an arc nonetheless. I'm hoping that this kind of motion will help in reducing jamming.


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## Sodbuster

" stolen by the post office employees in Denver "

Must of thought you had some bullion in their.

Keep up the good work. Cant wait to see it in action.

Ray


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## Cody Reeder

with the thick steel try cranking up the oxygen and start cutting on the bottom corner.( somthing my dad told me and it seems to work)


I am going to try building a jaw crusher my self , so I will be back to see how it goes


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## aunboy

That number 4 tip is the dog's bollox. I hit another delay when I ran out of grader blade teeth so I stopped in to the city garage and the road crew fellas donated a nice stick to my project. So I'm back at work!


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## grahmdiam

Good morning, today I started watching you tube videos about gold processing, refining, ect. and came across a site that manufactures gold processing equipment. This company makes various sizes of hammer mills. It was very interesting to watch everything from circuit boards to small electric hand tools, motors, door knobs, miscellaneous bathroom plumbing fixtures going through this hammer mill and the resultant scrap. There is also a video where they put 10 lbs. of powered circuit boards through a vibrating type of shaker table. The results are interesting and worth a watch. Try MBMMLLC.com


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## solarsmith

Im in denver and I have a home made jaw crusher. it has a 2 inch shaft 13 ton bearings 1inch wear plates bolted to 1/4 inch Press plates. end of shaft are turned 1/8th inch off center to make the motion of the moving plate a 1/4 inch circle. the botom of the moving plate is conected so it moves in a 1/4 inch by 1/8 inch oval circle. It takes a fist sized rock and makes it in to 50 % sand and 50% chips in a few seconds I think it runs at about 800 rpm with a 12 hp elect motor from an old wood lathe. jaws are 12inch tall by 8 inch wide with a 5 inch gap at the top. I need to add a fly wheel be cause it will jam but not very often. or a bigger motor . although Im very happy with it as it is. it dumps into a ball mill and in one pass the ore is down to 90% passing 200 mesh at 300 to 500 lbs an hr. Bryan in Denver..


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## bmgold2

I found some youtube videos that might be helpful for someone wanting to build a jaw crusher.

Gold Ore Crusher Tutorial part 1 https://www.youtube.com/watch?v=DYg9s_7fTdM

Gold Ore Crusher Tutorial part 2 https://www.youtube.com/watch?v=S9XyGiZsWF4

Gold Ore Crusher Tutorial part 3 https://www.youtube.com/watch?v=-szNj2zKvwI


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## darinventions

hi bubby,,I'm a bit of a mechanical engineer,,word to the wise...A Well known fact...dirt sticks to grease an oil,,where possible an if possible... take out your allenmites(grease certs)an use a auto feed grease cup,,,but instead of putting grease in it,,use graphite seed lubricant,,,,by using this method,it will almost completely eliminate friction wear,,,the only wear you'll sustain will be impact wear....this is hard to do when you first try it,,but the more times you do it the easier it gets,plus your stuff will seam to last forever,,,I did some experimental testing on an excavator... the one with grease was showing very visible wear within the first 24 hours of use(grease grabs dirt) the one retro fitted for graphite ran 50hours with no friction wear,an minimal signs of impact wear,,,,it maybe something to consider


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