Rock Breaker

I have no experience with hammers, but looking to buy a used one for a rock job. Problem is my odd sized machine, 17 tonne, and trying to find a breaker to suit.
My question is what’s the pros and cons of having a hammer that’s maybe too small or too large.
Ie: will I damage a 10-12tonner hammer with too much oil flow or speed?
And will I not drive a 20-25tonner hammer fast enough to break rocks?

The rocky reefs/shelf’s are hard red stone still imbedded in soil, with hardly any fractures in them. I can’t get them out of the ground and need to break them in there.

would a rock grinder work?

Rock moles dont work on boulders there typically to hard

It's never about oil flow with a hammer it's about weight and what kind of weight your machine can handle a 17 ton machines not going handle much more than 3000lbs hammer without stressing it

The thing with putting on to heavy a hammer is not handling the weight as much as the rebound off the rock back into the machine if you dont have the weight to hold the hammer down conversely if your hammer is way to small for your machine you can overheat the point and tool bushings causing excessive wear and or damage to the impact ring or piston damaging a point is not a big deal as it's easy to change but impact rings get wear and it will allow bad alignment on the piston causing it to flake from bad contact

What AZ said.

What specific machine do you plan to put it on?

CM1995 said:

What AZ said.

What specific machine do you plan to put it on?

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It’s an SK170-6 Kobelco.

Your looking at 2500 to 3000lbs hammers

Does that machine have 65 mm pins or 80 mm

The quick hitch seems to be a custom built thing. It fits 12tonner size attachments
It takes 65mm pins

I think the bottom dipper arm pin is an 80?


Just another thing to add to this scenario AzIron. this is a one off job. It Would honestly take 6-8 hrs max. Theres no rock work around my area, only this new farm track over a mountain range.
I might do a little concrete now and again. Mostly shed slabs, which are usually 200-300mm thick.

Then go rent a hammer on a machine from a local rental house and charge accordingly cause hammers are an investment and if you cant utilize them 3 or 4 times a year they are more headache than benefit I have 7 of them things they need periodic use or the seals go bad

AzIron said:

Then go rent a hammer on a machine from a local rental house and charge accordingly cause hammers are an investment and if you cant utilize them 3 or 4 times a year they are more headache than benefit I have 7 of them things they need periodic use or the seals go bad

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X2 on the advice. We've rented hammers for years before buying one last year for a large demo project which basically paid for it. If I were you I would definitively rent a machine with a hammer on it.

One of my clients is a sandstone quarry. I installed a hammer on a Komatsu PC200, got everything set up on the top of specs and then watched that tool tip dance all over that stone and didn't break a thing. Follow the advice above and rent something to find out if it will break at all. We ended up drilling and shooting all the time.

Yeah I did think of a rental hammer and or maybe a rental machine with a hammer, thanks guys. If I could’ve hit the right size for the right price I would be happy for it to sit around for a once a year but if concrete. But AzIron, thanks, I didn’t know they need to be used regularly otherwise the seals can go bad.

trouble is my location in rural farm country a fair way from any rental shops. The only close one is a 8tonner with hammer.

And John’s C’s report post above has reinforced a doubt I had. This stuff is dense red SandStone as well, so unless it’s a 30-40tonner then they won’t break apart.

back to the drawing board then.

Maybe the regional quarries business can blast them...........
I may dig around them some more and see if they could come loose with a bigger machine. I have access to a 330Cat.

thanks for the input guys.

You would be surprised what a 1500 lbs hammer will get thru even slowly

A 200 size machine can start pushing a 4000lbs hammer in a quart application I would think that's a waste of time in grading applications I have only had one job a hammer that size was not getting it we had to drill a pattern in some granite boulders so they would break

At the end of the day hammering has more to do with technique than brute force and if you dont have any experience you may find yourself struggling

Might give this a shot for the large boulders if you can hammer drill a hole in one.

https://www.dexpan.com/pages/dexpan-photos-rock-breaking-excavating

Hammers need to be stored upright with the steel down.

Thanks for that CM1995, but again location and availability of products and the farmers budget are all factors in this job.

hey AzIron have a look here and give us your thoughts. I reckon like you said, even if it’s a smaller hammer, perseverance and just hammering away in the correct spots will break these up enough to get them out of the road. There are natural hairline fractures in them so they should break up okay?

It’s abit hard to see them with all the dirt but there’s two shelf’s or reefs of rock

the lower big one in the purple consists of about two or three very large deposits

the blue one up the top should be easier as it’s multiple smaller rocks layered beside each other

but they are also like icebergs........... a little bit poking out and a monster bit underneath the ground

Couldn’t attach above

That looks like pretty course grain rock a course grain is typically softer than a tight grain then you get into granite and it doesnt have a grain structure

Also rock that's lose can break a lot easier up on the ground ten in in a 4 foot deep ditch you just keep working the edges


What you have looks similar to this my 2000lbs hammer on a 314 goes through it with good results

What’s your thoughts on Krupp hammers AzIron?

Never seen one in person I an really partial to npk they just run 3 of mine are as old as i am just rebuild and keep going. I have ran a few epiroc witch bought out atlas they seem decent Stryker okada and even cat hammers as well as bti are ones I would be willing to spend money on mainly cause I have a little experience with them

Cat hammers are not all that great in my opinion and I dont think okada is much better Stryker doesnt build a component based design it's more unibody witch is really limited to rebuild same with cat

AzIron said:

Never seen one in person I an really partial to npk they just run 3 of mine are as old as i am just rebuild and keep going. I have ran a few epiroc witch bought out atlas they seem decent Stryker okada and even cat hammers as well as bti are ones I would be willing to spend money on mainly cause I have a little experience with them

Cat hammers are not all that great in my opinion and I dont think okada is much better Stryker doesnt build a component based design it's more unibody witch is really limited to rebuild same with cat

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Let me add a little bit of (what little) knowledge, and personal experience, I have to this.
I agree that Cat hammers have, in my opinion, not been my first choice in the past. I believe that they used to be made by Rammer and the way they were designed caused them to destroy themselves and were expensive to repair/rebuild. They would hit pretty hard though. Cat has recently changed their hammer design (I don't know if now made by Cat or who?) so I cant speak to their reliability or performance. CM1995 currently has one and I'm sure he can comment from a more informed perspective.
Striker (the hammer that I currently own) is made by Toku. This is a Japanese brand that has been making hammers since the late 40's. Striker is how they are branded in the US and they are also sold under the Komatsu brand world-wide. Toku used to make BTI hammers and, again-in my opinion, how BTI made a name for itself in the hammer market. BTI hammers are now junk (in my opinion). BTI was bought by a large holding company and now sources their hammers from a Korean MFR (I don't know specifically who). If one can find an old TB series BTI they are made by Toku and can be serviced/supported well worldwide. My breaker is a 5,500# energy class breaker (smaller of the "large" size breakers) which I bought new in 2017. It is a TNB190 and it is comparable to NPK's GH-12 breaker. It probably has about 400-500 hours on it now and the only thing I've had go "wrong" with it is one (1) bolt came loose on a cover plate recently. I've gone through a few hoses, and a couple of Stucchi couplers, and have just installed my 3rd tool, but NO mechanical issues thus far (YAY!). I also have a friend who runs 7,500# and 10,000# Toku hammers (started out with Cat hammers) and he reports that they are extremely durable, and are relatively easy and inexpensive to rebuild. Since I have not been inside one yet so I can't confirm or deny whether, AzIron's comments (regarding "component based design") are correct. When I compared NPK to Toku (during my purchase research) they seemed to be very similar in design. Though each MFR has a slightly different design they seem to employ the same components. Both have replaceable upper and lower bushings, both have anti-dry fire mechanisms, both employ only (2) moving parts, both use a nitrogen cell to recycle energy, etc. Toku does employ a (2) pin tool retainer system vs. NPK's single. If there is a difference in which components are on them I am not aware of it. I think both are good hammers. AzIron has stated (in other threads) that they use (and prefer) the older NPKs based on performance, ease of rebuild, inexpensive initial investment (many older NPKs are out there in the used market) and simplicity. If there are some differences between the older NPKs and newer, maybe he could shed some light on them. I did narrow my hammer choices down to Toku and NPK but went with Toku due to my friends experiences. In addition to those we had a mutual acquaintance who "bare" rented several wheeled excavators with Toku breakers (this was in the 80's and 90's so they were older BTI branded-made by Toku-units) and he reported that he had almost no repairs on those hammers. I would be afraid to let anyone else run my breaker let alone send it out for any "Tom, Dick, or Harry" to run unsupervised. Those unsolicited comments/experiences spoke volumes to me. NPK makes fine hammers and I would not likely hesitate to own one. There are a ton of them out there and the only negative thing that I have heard about them are that they can have a lot of "pulse" energy (surging in the hydraulic lines with each hammer blow) and some reports of the the bore moving inside the housing. As it relates to the other brands I don't have much experience. I do also have a breaker for my mini (a Bobcat brand 950) which, I believe is a Stanley breaker and it has been pretty reliable for me (bought it used in +/- '08). HEF member KSSS claims to love Okadas but I don't know what size units he is running. Since you will likely rent it may not matter which brand you go with as you will not likely use it long enough for any issue to arise from a sub-standard brand.
I mentioned size in several of my comments because size is critical for breaking rock. Breaking concrete is EASY when compared to breaking rock (particularly in situ bedrock). Concrete is usually about a 3,000 psi material, and some types rock can be over 20,000 psi. Obviously the energy it would take to break concrete is substantially less than that of rock. Keep that in mind when you go to the local rental store and think about renting a hammer mounted to a mini-ex or a rubber-tired backhoe. Those will likely be 750-1000# (on the high end) hammers and there is rock out there that will tell my 5,500# breaker to "F"-off.
That last statement reminded me of how good Striker's support is. I first bought a TNB110 (3,000# breaker) and found that it would NOT break most of the rock I was encountering at my sites. I showed some video of it working (or rather trying to work) to the president of Toku America at the '16 Con-Expo. Based on that he sent me (2) brand new-on the pallet breakers (the next 2 sizes up) for me to demo at my jobs -at no cost to me. I chose the larger one and they gave me back my full purchase price for the TNB110 as credit towards the TNB190 that I have now. For me that demonstrated HUGE integrity and commitment to customer satisfaction!
The last thing I would say to you is relative to your last post. Whether you buy a Krupp, or any other brand, be sure to "but it right". If buying used quality rebuilt units can be found at specialized "hammer" repair facilities/dealers (at least here in the US). Auctions are good place buy hammers (at massive discounts) but the term "BUYER BEWARE" applies here. If I were to buy at an auction I would be sure to pay a price that still allows me to do some serious repairs/rebuild to it (should it turn out to require it) and to cover the hassle of that process as well.
Good luck!