Best rotary hammer (re-visit to splitting boulders)

   / Best rotary hammer (re-visit to splitting boulders) #1  

gunns

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Can't believe it's been two years since I gave thought to splitting up the boulders on my property. Been sidetracked with other responsibilities. Now I'm ready to start splitting. I've been looking at drills, mainly Bocsh, DeWalt and Milwaukee. What do the rock splitters here recommend? SDS-Plus vs. SDS-Max. At Home Desperate and Lowes I've seen plenty of SDSplus bits but no SDSMax bits. It's my understanding that the Max are the stronger - right?

I've been considering the three below:
Bosch 11240, 10 amps, impact energy 5.2ft.-lbs.
Dewalt D25501K, 12 amps, impact energy 8ft.-lbs.
Milwaukee 5317-21, 10.5 amps, impact energy 5.5 ft.-lbs.

All three are priced between $390 and $430 with the Dewalt being the most expensive but with 50% more impact energy. All three are also 1-9/16" models. Has anyone used any of the three or has a better suggestion on make/model?

I know this question will open up a Chevy vs. Ford type of war but which drill seems to be a favorite. I have a bunch of large boulders (some VW size) to split and will make use of the split rock around my property and will try selling as slabs and steps etc.

Any help is appreciated!
 
   / Best rotary hammer (re-visit to splitting boulders) #2  
Consider a Hilti.
 
   / Best rotary hammer (re-visit to splitting boulders) #3  
A little off topic: What are you using to split with after you make holes?

Bruce
 
   / Best rotary hammer (re-visit to splitting boulders) #4  
The best hammer drills made are Hilti, but you will pay for the quality. Among hammer drills and breakers the large 1-1/8 hex bits are what you would want for breaking up concrete. Look at models such as the Bosh brute.
Amazon.com: Bosch BH2760VCD 120-Volt 1-1/8 Brute Breaker Deluxe Kit: Home Improvement

If you are breaking up pieces as big as cars you need to switch over to air or hydraulic power. Probably be better off to rent a air compressor /breaker or a skid steer with a breaker bit.

You will drive yourself crazy trying to break up large rocks with sds and sds max hammers. Like using a push mower to mow 20 acres.
 
   / Best rotary hammer (re-visit to splitting boulders) #7  
My suggestion: Rent a comparably-sized rotary hammer for a day in order to determine it its the right tool for the job. I think you're gonna be waaaaaay underpowered with a 10A rotary hammer.

SDS Max bits are more expensive, but there's no comparison to SDS+.

I have a Makita HR4002. It's priced right and doesn't beat the **** out of you.

For bigger jobs, it's hard to beat the Bosch Brute. That's my go-to from the rental store.
 
   / Best rotary hammer (re-visit to splitting boulders) #8  
Assuming that you have rocks that are at 3 feet x 3 feet or larger, you will want at least an SDS Max drill, and probably a large rotary percussion drill. They will typically have 12+ amp motors, and 20+ pounds of weight so that the larger impact energy drives the bit harder and doesn't shake you to pieces. You will need a rock bit for the drill, which typically has an X point on the end, and is typically 2+ feet long or more, depending on how deep a hole you want to drill.

You don't want a demolition hammer (similar to a "jack hammer") unless you are trying to break up rock, such as you might do with sedentary rock like shale.

But backing up a bit, what are you intending on using to split the rock. All the drill does is to drill a hole (hopefully quickly and without beating you to death). Expanding cement typically wants a hole of one size (1 1/2" or so), and rock blasting material wants a smaller hole. You need to determine this before getting a bit, and I agree with the other folks, rent a drill for a day and see that the energy / power is about what you want, and then buy your choice of drills that are similarly sized.

I happen to have a large (14 amp / 11 joules of energy) Dewalt drill, and it is a beast for drilling holes. It is similar (previous model) to D25723K 1-7/8" SDS Max Combination Hammer with E-Clutch/2-Stage Clutch | DEWALT Tools. I have used it to drill holes and split granite rocks and it did the job well, but even with it, it will take time to drill dozens or hundreds of holes (depending on how many rocks you have to split up).

The step up from that type of drill is a pneumatic (air) drill, which will be 2-3 times as powerful and take a large compressor to generate the correct amount of air to operate it.

So my suggestion is to figure out what agent will be used to split the rock, and what hole it is looking for, how often the holes have to be drilled in a large rock, etc., and then when you have some fairly well known requirements, figure out the drilling mechanism.
 
   / Best rotary hammer (re-visit to splitting boulders) #9  
What ace10 said +1... There are multiple levels of these things, but the electric ones tops out at some point. You don't indicate how big these rocks are, what type, or how many. Go rent a demolition hammer (the biggest size) and see if it does anything. SDS Max is the biggest size (also the spline ones are in the top end). If renting one of those for a day does not bring joy to your life, then you will need to rent a towable compressor and a jackhammer to have any luck. If you find it does what you want, then go buy one and have at it, at your leisure. Hearing protection more than recommended (required), and a respirator would be wise if you are doing this a lot. Safety glasses too as these things can throw chips at times, and they only seem to aim for eyes...
 
   / Best rotary hammer (re-visit to splitting boulders) #10  
Journal of Light Construction is a magazine that does real tests on tools out on jobsites and then posts them. A few years ago when I was looking for a SDS Max they had just done a review of all the brands available in 1 9/16's size. The Hitachi won hands down in speed. When comparing costs, it was mid range with Hilti being the most expensive. I've had one Hilti tool and I wasn't very impressed. It was a framing nail gun and it would just start coming apart with use. I ended up throwing it away for a DeWalt that wasn't any better and now have a Hitachi that is great!!! Bosch and Makita are my two favorite brands, but I'm very impressed with both my Hitachi SDS Max and framing gun.

I bought mine online, but forget who. Maybe Amazon? Anyway, for bits I go to United Rental, who has a decent selection of SDS Max bits and attachments. I only have a few bits because that seems to be what I use the most. I also have the jackhammer pointed tip attachment that is great for taking out concrete. There is a shovel attachment for digging extremely hard clay that is more then worth the money if you ever do any plumbing work under a house or through a concrete slab that you just jackhammered out the concrete. And if you ever install ground rods or rebar into the ground to hold landscaping timber in place, the post driver is amazing!!! Just pull the trigger and let the weight and hammering of the tool do the rest!!!!

Eddie
 
 
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