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Discussion Starter · #1 · (Edited)
Ive been thinking of building a small jaw crusher for the past 3 months and decided to made a very small one today to see if it would work. The jaw plates are 1/4" steel 4 1/2 inches wide and 9 inches tall. Sides are 1/8" plate. One jaw plate i welded solid to the sides. The other is attached to a Crank at the top to make the back and forth movement. The bottom of this plate has a piece of steel( toggle) Like this 0-0 that goes back to a solid crossbeam between the sides. This let the plate move up and back when the crank is in its up most position to force the rock down into the jaws. A spring holds the bottom of this jaw so the toggle doesnt fall out.

The good news is that it actually crushed some concrete. The bad is that my crankshaft is not straight and binds. The sides also flexed a lot.

Ill get some pictures of this crude contraption tomorrow.
I think im satisfied with my results so the next step will be to make one about 12" x 18".
Anyone ever make one before?
 

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Discussion Starter · #2 · (Edited)
Heres a couple pictures. For some reason i was in a rush to play with it and didnt focus on fitting everything up the way i should have but it crushed some concrete.
 

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Very interesting!

I've been following along but just don't know what to say :trink40:

Imagining what it looks like and then seeing the pictures...well, it's completely different from what I thought I'd see. Will the steel be hard enough to crush concrete and be durable enough for a long lifespan? Oh, and how big is the opening shoot that ingests the raw stuff before it's crushed?

It's a great idea and I don't think I've seen one that's homemade before!
 

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Discussion Starter · #5 ·
I just used steel i had laying around for this model. I made it to see if i understood how it worked and i wanted to make sure it crushed some concrete before i spend money on this project.
I adjusted the opening at the bottom of the jaws this afternoon to about 3/8". I fed it small chuck of concrete about 2" in size and ran the crusher off of a 1/2" drill. This resulted in stone from 3/8" down to dust. I also found slower rpms(200-300) are better than faster speeds(800rpm). At the faster speeds the concrete just floated between the jaws with little crushing being done. I also need to add some more ridges to the jaws so the concrete cant slide up when the jaws close.

The bigger one i want to make will be made from thicker plate. 1/2" jaws and 3/8" Sides. 3/8" rebar placed vertically on the jaws and staggered from jaw to jaw. Belt driven crank and a large flywheel. I think ill mount the crank on bushings rather than bearings. Good idea? Would bearings take the abuse? Would constant greasing be needed with bushings?
 

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After working on them for 32 yrs, you're headed in the right direction. If you want it to last I'd use AR(abrasion resistant) plate as it won't bend as easy. From your description of the larger one planned I'm guessing you've also worked around them. From what I can see I think the eccentric needs less stroke. The length and angle of the toggle board above the jaw seat will determine how much action you get at the bottom which is where most of the crushing is done. You probably already know all this, but bear in mind that the shorter the toggle is and the more angle it has, the more HP required and more stress on the frame and movable jaw. As for bearings it depends on how much $$$ you want to put in it. I'd use pillow blocks for the frame and one or two, depending on space availability, split sleeve bearings for the eccentric.
As for speed, it will crush better at low RPM. Even at 250 RPM the flywheel will need to be balanced good or it will probably break the eccentric shaft eventually. Even at that speed you don't want to be around when that happens!!! Up to a certain point the weight of the flywheel will determine how much horsepower you need.
Keep on posting pics, I'm intrigued w/ this!!!
HTH,
Mike
 

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Discussion Starter · #8 ·
Mike,
Ive never been around a crusher except driving past them in the quarry and you cant see much. I just looked it up online and found a cutaway view, then copied it. Im doing this just for fun.

Im not too concerned about it lasting forever so im just going to use mild steel. I plan on making the jaws easily replaceable if the wear or bend. The eccentric shaft has about 1 1/4" stroke. Should it be shorter?
I changed the length of the toggle board to adjust the final product. Is that acceptable? I have the toggle board set up so its on a slight upward angle. I think i need to make it the full width of the jaw unlike the mini model i made which is only half the width.
Ill look into those bearings. Thanks for the advice.
Frank



After working on them for 32 yrs, you're headed in the right direction. If you want it to last I'd use AR(abrasion resistant) plate as it won't bend as easy. From your description of the larger one planned I'm guessing you've also worked around them. From what I can see I think the eccentric needs less stroke. The length and angle of the toggle board above the jaw seat will determine how much action you get at the bottom which is where most of the crushing is done. You probably already know all this, but bear in mind that the shorter the toggle is and the more angle it has, the more HP required and more stress on the frame and movable jaw. As for bearings it depends on how much $$$ you want to put in it. I'd use pillow blocks for the frame and one or two, depending on space availability, split sleeve bearings for the eccentric.
As for speed, it will crush better at low RPM. Even at 250 RPM the flywheel will need to be balanced good or it will probably break the eccentric shaft eventually. Even at that speed you don't want to be around when that happens!!! Up to a certain point the weight of the flywheel will determine how much horsepower you need.
Keep on posting pics, I'm intrigued w/ this!!!
HTH,
Mike
 

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This looks like the perfect gift for that relative doing a stint in the big house or the man with a new backhoe.
Really awesome looking little contraption. You do need to scale it up though if your going to make some piles big enough to dig with your 6018. :fing32:
 

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For your larger one I'd make it about a 3/4" stroke or a little less, takes less HP that way. As I mentioned the length and angle of the toggle board determines the stroke at the bottom. The shorter the stroke, the more uniform the product. We always used stacks of shims between the stationary toggle seat and the frame to adjust the opening. You could put in a slightly shorter toggle board and more shims to get more stroke, but it reaches a point where its stressing everything too much. Just depends on how hard the rock is. Yes, I would make the toggle board full width so the load is spread across the full width of the jaw.
Keep it up and post lots of pics and good luck,
Mike
 

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I have plenty of large limestone rocks that I would like to crush for my driveway. If you get something workin I would be interested in the plans. For now, I am raking the small rocks and using them to fill the pot holes. Unfortunally the pot holes grow faster than my yard can produce small rocks.
 

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If you consider concrete withstands 2000-3000 PSI you can make some estimations as to what you'll need for bearings and such. The tricky part is guessing at how much surface area of the concrete will be touching the plate because that directly affects how much pressure you need to crush it.

A mounted bearing with 1" ID can support about 3000 pounds, so two (one on each side) would of course double that. A bronze sleeve bearing would support comparatively more pressure, however, and due to cost and the slow rotational speed that this will likely be operating I agree with your plan to use them instead.

Regarding the appropriate stroke you need to specify how much torque you're going to be applying to your flywheel. If you don't know the torque value you can calculate it from the HP of the powering engine and the RPM of the flywheel (which I assume you're going to gear down). I'll leave the calculation of the moment of inertia of the flywheel to someone else to figure out ;)
 

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Do a Google of jaw crushers. Your concept is pretty good but you’re in for a learning experience once you try to crush stone. Concrete is about 3000 psi but even soft stone is over 15000 psi. You'll need some serious steel and bearings. I used to own a quarry, trust me you’ll save a ton of money if you just buy the finished product.
 

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Discussion Starter · #14 ·
Do a Google of jaw crushers. Your concept is pretty good but you’re in for a learning experience once you try to crush stone. Concrete is about 3000 psi but even soft stone is over 15000 psi. You'll need some serious steel and bearings. I used to own a quarry, trust me you’ll save a ton of money if you just buy the finished product.
I know i can get RCA for 6$ a ton so im not doing this to save money. Its just something im interested in building. Its going to make a nice winter project.
 

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I know i can get RCA for 6$ a ton so im not doing this to save money. Its just something im interested in building. Its going to make a nice winter project.
Well, I'm not informed enough to even have an intelligent comment. But I was reading through the thread, and I was interested in the idea, but couldn't for the life of me, figure the "why" of this endeavor. Until this last quote, it was finally revealed! I can go along with that answer. I wouldn't personally, but it is a cool idea, and obviously, it is something you know a little(lot) about.

Carry on, and be sure to show photo's of the build. I'd love to follow it.
 

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I built a rod penner to crush rock that worked real well , had 6 hardend steel 1in rods run on 2 3cyl crankshafts.
 

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I built a rod penner to crush rock that worked real well , had 6 hardend steel 1in rods run on 2 3cyl crankshafts.
Mike: Any chance you could elaborate on the design and/or give some pictures or point to some pictures of the internals on the web?

I am trying to build one small (maybe 6" x'12") but I have many unknowns just before I start. I am looking for someone to chat about these crushers. Specially if have an idea of the internal construction.
I wan to avoid the steep learning curve and listener to others that did it helps immensely.

Thanks, Wilson
 

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I had site that made crushers for very small operations in Africa and such, they were operated by Hand :eek:mg: they came in one or two person powered units with what looked like fair sized flywheels.
 

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Discussion Starter · #19 ·
well im back home after staying at a relatives house for a month while they were away. I need to sell a few things to make some room for this build. anyone interested in my 646 its in the craigslist/ebay section
 

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Discussion Starter · #20 ·
Mike: Any chance you could elaborate on the design and/or give some pictures or point to some pictures of the internals on the web?

I am trying to build one small (maybe 6" x'12") but I have many unknowns just before I start. I am looking for someone to chat about these crushers. Specially if have an idea of the internal construction.
I wan to avoid the steep learning curve and listener to others that did it helps immensely.

Thanks, Wilson
Check out this link. http://www.youtube.com/watch?v=zvkEn6oytV8&feature=related
 
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