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CRUSHER BUCKETS ATTACHED TO EXCAVATORS

DGODGR

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Dec 18, 2009
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I have an MB BF 70.2 crusher bucket and would like to start a discussion about them (or at least crusher buckets). I am using it for crushing on-site shot rock, or hammered rock, into a use-able product (structural fill, road base, or backfill). I have been having some issues with it and I can't seem to find any source of information or support. The support from MB is almost non-existant. I can call and get parts but there is no fruit when it comes to getting any answers as to why I'm having the issues that I am. I would absolutely love to have a disussion with other owners/users of this, or similar products, to share insights and knowledge. Please chime in/introduce yourself if you think you have something to contribute to this topic. I am more than willing to share what information I have gathered in return.
I have had mine for about a year and have crushed limestone, sandstone, gneiss rock, granite and concrete. I have replaced several toggles (always break at the weld of the narrower end (at the jaw support), have already been through a set of dies (seem to have worn out very quickly), have replaced the bushing at the end of the preload shaft (recommendation of MB to address the toggles breaking), and I am now seeing cracks on the jaw support (at the corners of the rectangular pocket that holds the toggle). Any advice would be appreciated.
 

funwithfuel

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Are you adjusting your close side too tight? Are you using the recommended lubricant for the toggle linkage? What we do , we set our close side setting to what we think, then we ball up a big chunk of tin foil and feed it into the jaw to see what we get. Measure the tin foil, that is your true close side setting. I am speaking from experience with full size jaw crushers, but your implement seems to operate very much the same way.
BTW is your feed material free of rebar and other non-crushable material. Oh and are you choke feeding it?
 

DGODGR

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Thanks for the reply. I was starting to think that there would be no responses. The MFR does not recommend any lubricant at the toggle. I would think it would only pack up with dust in a matter of minutes anyway. We are crushing mostly to 3"-. I can go down to 1" and can open things up to about 6" material. I have not fed aluminum foil through it. We just check the material that it produces and adjust shims accordingly. The crusher is a jaw type so it is very similar to any other jaw. The main difference is that I can change the angle while crushing and can dump out any jams that may occur (most of the time). Our feed material does not usually have rebar in it, and if it did, the machine could crush regardless. There is not any belt or anything for the crushed material to fall on so rebar is only a problem if too big to fall through. I generally pre-break concrete to remove rebar anyway. We do get a lot of dirt running through (I'm sure that increases wear and slows production) but this is the closest thing to "non-crushable" material that we may run through. Ironically most of the jams we get are when we feed mostly clean stones into it. I have to be careful when "choke feeding". If one tips the bucket up too fast it will often jam. I think one of the drawbacks with this machine is that it is under powered (hydraulic motor to belt) and/or under flywheeled (could possibly use more flywheel weight). In general I will feed it as fast as I think it can take it. Just because of the way the bucket works it can only choke feed for short periods of time. This is when it is first tipped up and is full. As the crushing process continues the bucket empties and one then gets another scoop.
 

funwithfuel

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Well after studying the drawings and spec sheet for it, i see what you're saying about the material running out quickly. So my next question , are you feeding the machine static or do you have her running, scoop the material and keep feeding while shes running. Is your machine up to task, by thast i mean do you have adequate pressure and flow at the tool. Are you running in hammer or shear
 

funwithfuel

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37 gpm @ 3100psi thats a high demand when performing bucket arm and boom. You've got to be set up for 2 pump flow or auxiliary pump, depending on what hoe you're running
 

DGODGR

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The machine will always take hydraulic priority over the attachment so one can't really keep things spinning while scooping more material. The best way I have found to work it is ti scoop the feed material and then engage the attachment prior to tipping it up (which is when the material starts to fall into the jaw). It doesn't really have enough power to engage the tool when rocks are tight against the jaws. It needs to rely on inertia to work effectively (same as any jaw I would think). Settings (hammer or shear) depend upon the machine in use. It seems that you are really asking if we are using a mono or bi-directional circuit when running this attachment. We have to run return oil straight back to tank (mono-directional) or we can't get flows without too much heat. Haven't even tried but the tool requirements are as such. One machine is a '17 Deere 245G and the other is an '03 Cat 315 CL. The Deere has many attachment pre-sets (customize-able) and one only has to select the attachment through the monitor. The Cat required an aftermarket attachment augmentation circuit (to get 2-pump flows) that requires manually changing to mono-directional and manual adjustment of the pressure relief cartridge to reach tool requirements. Both have been set/checked with flowmeter.
 

DGODGR

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Running the tool on the Cat (40k pounds and less pump out put) is asking a lot of the hoe and the Deere (60k pounds and has (3) hydraulic pumps) has a much easier go of it.
 

funwithfuel

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Do either of your hoes have a toggle option on the joystick for hammer. Meaning , you press the switch, it stays on til you press it again. This would keep you flywheel in motion. The that would allow you to run the rest of the machine slowly off one pump.
And yes, i was making sure you had a straight path back to tank. Thanks for clarifying
 

DGODGR

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Both machines only run a momentary switch for attachment activation. If you think about the process it really doesn't make much sense (to me anyway) to keep stealing hydro power when not actually crushing. To clarify...These type of attachments can barely get the same output (in a day) as say a 100,000# mobile crusher does in an hour. I think a big part of that is because the mobile crusher is constantly crushing while the support machine keeps the feed hopper full (I know-way over simplified). On the crusher bucket much of the time is wasted trying to fill the bucket. Doing this any slower would be very counter productive especially considering that it only takes a couple seconds to get the flywheels up to speed.
 

funwithfuel

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Ok. Thats all i really got. If your jaw is running at speed, the materials entering the throat wont be able to jam or stall the jaws, thereby reducing stress. Momentum and speed are your friend in regards to the jaws. Good luck and i hope someone else can help
 

Clballengee

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Feb 5, 2018
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Reno, NV
I am a Rep from MB Crusher. First I want to apologize that you have not been taken care of. Please contact me so I can get you the service answers you need
 
Last edited:

Clballengee

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Feb 5, 2018
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As for the machine it can actually be set up a little higher on the BF-70 I would run it at 40 GPM and 3200 PSI. and with the CAT I have had to have a CAT tech come out and set it with his computer. I have looked at Ritchie specs and it looks that the JD puts out 118 GPM or roughly 55 GPM. The Cat looks like it is running at roughly 67 GPM or 33 GPM. I would suggest using the John Deere.
 

DGODGR

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I received your PM. I'm glad that you have reached out to me Clballangee. I have been waiting for a reply from MB for weeks now. The crusher has been partially disassembled for weeks now. I will call you tomorrow.
 

tylermckee

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Jan 9, 2006
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washington
We just picked up a bf120, so far we have had one small hickup with some bolts coming loose but they have taken care of us immediately. They were going to fly up and fix it but I said it's not necessary as I can fix it in an afternoon. Time will tell how it holds up, so far I've been happy with the production it puts out, especially given the nature of the rock im feeding. It is some extremely hard rock.
 

DGODGR

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Hi Tyler.
Glad to hear that you are satisfied with production rates and your attachment thus far. This is promising. One must keep an eye on things because things do like to come loose (as I'm sure with all crushers to some degree). It has been a long time between crusher jobs for us. My crusher was in a state of disrepair for quite a while. I had lots of cracks on my jaw support. MB offered to make the repairs if I shipped it back to them. I decided to take them up on it because this would allow them to look over the entire unit to see of they thought that there might be any other contributing issues with it, I would not have to be the one to disassemble the entire unit (to make said crack repairs), and they said that they would also come out to make sure that we had everything set up correctly. The shipping ended up costing me $2k and the unit was delayed a long time (at least a month after promised delivery date). We missed a crushing job because of it. When we got the unit back MB said that the flywheels were out of time (that the compression/friction bolts had come loose and allowed the flywheels to rotate on the shaft which allowed them to get out of balance). They said that we needed to check this alignment and tighten those bolts daily. I decided to check it prior to using it as baseline. I followed MB's directions and, ironically, it was delivered out of time! We ended up loosening the bolts and putting the flywheels back in time/balance. To date nobody has come out to check on things as promised (it has been 4 or 5 months now). In retrospect I would have rather done the work here and had my welder make the repairs as the weld quality appears to be less than what I would expect from professional welder. We have just recently put it back into service and we are crushing limestone tallus that is about 2-3' thick. Production is still only about 10yph when trying to make 3"-. This is about 1/2 of production rates claimed by MB (from the brochure).
You have said that your production rates are meeting your expectations. This is great news! Can you please provide more details? I would ask what material you are crushing (you said it's very hard)? What size are you crushing it to? What is your feed size? I would understand if you would prefer to discuss this privately. If so please PM me. I think that the sharing of information could be beneficial to both of us.
 

jaclo

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Apr 22, 2014
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This is an old ass thread, I was wondering if anyone has had any more recent experience with the MB, or Xcentric buckets. Looking to possibly invest and this thread isn't very encouraging.
 

DGODGR

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I have never heard anything from tylermckee (regarding his crusher) and I have nothing better to report than what I have already posted. In summary of my experience with MB I would say that the customer support is VERY poor and production rates are nowhere near what they claim. It is safe to assume that they would argue that the material is different (MB's production rates are based on concrete) and my feed size is too big. In fact this is what they are telling me now. To that I say that I get the same production rates when crushing concrete as I do most of my rock. Rock is usually harder than concrete and therefore should crush faster (will take less impacts to reduce the material to the size that will fall through the crusher). Dirt, especially if moist or wet, will reduce production considerably. As it relates to feed size the only production reduction I see is from jamming and hot stalling. This definitely makes a difference but I still have this happen when feeding smaller rock too. Regardless the salesman told me (before I bought the crusher) that you can feed any size material that will fit into the opening. Now that I have purchased it they are telling me to feed 10" minus. I am usually trying to make 3"- so that fits into the standard crushing rule of thumb which is a 4:1 reduction ratio (a rule that I have since learned). THIS IS NOT WHAT THEY SAID PRIOR TO THE SALE! They have yet to come out and verify flows and pressures (though I have done so several times-myself and with other mechanics) nor come see what is happening for themselves. They have made repeated promises to do so but never do because they are too busy trying to sell more crushers to others. They don't say that in those exact words but what else would it mean when they say that they are really busy getting ready, being at, or gearing down from one show or another. I've had this crusher for over 2 years....That's a lot of time to be able to make time to support a customer. Even if they put the customer off to go do trade shows. I'm not exactly sure what difference it will make anyway....They don't really have anyone there with much crushing experience anyway (other than when they have been around others who use their product or limited experience with demos). Initially they were pointing the finger at my Cat 315. Not the fact that it is really too small for the BF 70 (they are actually the one who recommended that I mount the 70 to the 315) but the fact that, in their experience, they have the most trouble trying to set their attachments up on Cats than any other brand. Ironically I get the same results regardless of which excavator I mount the bucket to ('03 Cat 315CLC or '17 Deere 245GLC). The only good news I have about this is that (based anecdotally on the opinion of the friend who recommended MB to me (very early version BF 120 mounted to a Cat 330), another contractor who I was introduced to by MB (BF 90 mounted to a Deere 450) and from tylermckee above (BF 120 mounted who knows what) the reports on the larger units are that they do not seem have the same issues. BTW, I would love to be wrong, or proven wrong, about this. Not the reports of larger units having more success/less issues but rather that MB could help me figure out why the unit that I bought is not meeting my expectations in durability, production and post-sale support. Expectations that were set, in part, by them.
As it relates to the Xcentric I have no clue. I would like to try one but have yet to see one in my area. I can say that the Xcentric ripper does not seem to work as claimed in the limestone that we have in my area. I have talked to someone local who has purchased one (ripper) and he said it works good in sandstone. I'm not sure how much presence/support that Xcentric has in the US anyway. To my knowledge MB has been in the US market the longest and their support/presence leaves a lot to be desired (if that says anything about the others). The other major player (in US anyway) is the Hartl. I've not heard to much good about them either (admittedly all rumors and hear-say) except from Mr. Hartl at Con-Expo.
I think that a couple of things (though maybe obvious to some) are worth mentioning here. Salesmen generally say whatever they think will get them a sale (may not apply to all salesman-use your gut instincts and do some homework before you buy). Crushing is not as easy as it looks in videos. There are a plethora of things that will effect production rates and/or costs. Talk to as many people as you can (especially those with crushing experience IN YOUR AREA AND/OR WITH THE MATERIAL YOU ARE TRYING TO CRUSH. Know that any issue a dedicated high HP crusher (stationary or mobile/track mount) may have, or most circumstances that may effect one, will be exponentially more difficult for a relatively low HP crusher bucket to overcome. I hope this helps. Best of luck to you and please report back if you end up getting one or find any info that would contribute to this thread.
 

DGODGR

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I'm hoping to revive this thread. It has been over a year since the last post so hopefully there are more people out there with experience to contribute to the thread. I still have not resolved any of the issues that I have had in the past. I have since purchased a grizzly to process my virgin shot to 10" minus prior to feeding the crusher. I had (2) jobs lined up when I bought it but neither one came to fruition. What I'm saying is that I haven't used the grizzly yet nor have I run the crusher in about a year. I have been stock piling some material at my yard so I may just run some to see what I can learn.
 

CM1995

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I've been interested in one for site demo jobs we do as there is always some sort of concrete being removed. These jobs may have 60' of curb and gutter or 10K sf of 4" concrete slab to haul off. A crusher bucket however slow would be a better alternative to trucking and dumping.

Subscribed to the thread to see if anyone else has more info. DGODGR you going to Conex?
 
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