How can I Split Granite Stones?

david12danielAugust 26, 2006

I am building a dry, free-standing stone wall and am using some granite stones from around my property. A few of the stones are a bit large to use in their present state and so I'll need to split them. What would be a few of my options to get this done? The two most important factors in getting this done are cost and ease.

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baymee(LehighValleyPA)

Buy a hammer drill and some masons wedges, about 4, and you can split most rocks.

You'll have to learn how to read the direction of the grain.

    Bookmark   August 27, 2006 at 6:03AM
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david12daniel

Great, that's what my preliminary research indicated I would need for tools.

Do you know of a resource that could help in learning how to determine the direction of the grain?

    Bookmark   August 27, 2006 at 4:20PM
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baymee(LehighValleyPA)

I don't. Even masons with tons of experience get it wrong sometimes. However, you might still end up with a straight face, but not cornorstone material.

    Bookmark   August 27, 2006 at 4:27PM
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baymee(LehighValleyPA)

Actually with an electric drill, the process isn't bad at all. I'm thinking of hand drilled rocks where hours of drilling sometimes resulted in a bad break.

    Bookmark   August 27, 2006 at 4:29PM
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DrynDusty(z8 AZ)

My grandfather was a blacksmith and stonemason in rural Michigan. He died in 1948. I'm told he could split most rocks with a single blow, although he stood about 5 foot 4 or so. He would take a load of stones to the county fair and challenge anyone to split one with a sledgehammer. I'm told he never lost a bet.
I wish I'd known him better, and maybe learned blacksmithing and/or stonemasonry. Norm

    Bookmark   August 27, 2006 at 6:27PM
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david12daniel

Ok, thanks a bundle for the info. I need to get a hammer drill anyway for some work I'll be doing down in my basement, so it will hit two birds with one stone. hmm.. no pun intended :)

    Bookmark   August 27, 2006 at 7:24PM
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baymee(LehighValleyPA)

Norm, I don't know what type of rock it was, but here in the Appalachian range, we have rocks that a sledgehammer will bounce off of.

I ruined my wet-saw diamond blade trying to cut through "iron stone". I got through a fist-sized rock and the diamonds were worn out.

I did some checking and found that iron stone is harder than granite and the blade is about $250 or more. End of project.

    Bookmark   August 27, 2006 at 8:22PM
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maineman(z5a ME)

Baymee,

"I got through a fist-sized rock and the diamonds were worn out."

And they told me on TV that diamonds are forever. (grin)

We're digging a drainage ditch and have encountered several large, very heavy rocks, which I plan to try to split using the methods suggested here. I hope our rocks aren't iron stone. I never heard of iron stone before. Is it some kind of iron ore? What does it look like?

MM

    Bookmark   August 27, 2006 at 11:05PM
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baymee(LehighValleyPA)

That's what the masons call it. I don't know the proper name, except that it is an igneous rock. We do have alot of iron ore here. Bethlehem Steel used it during the Industrial Revolution and much of this mountain has been undermined for iron ore. It looks grey or black/grey.

I doubt that you can crack a rock embedded in the soil because it can't move sideways. You may need a blasting crew.

    Bookmark   August 28, 2006 at 5:48AM
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DrynDusty(z8 AZ)

I hope I never am pitted against one of your iron stones, baymee. They sound like tough competion. Maybe they should hang them on the sides of tanks in Iraq? I mean, if they can't get the good armour, why not?

Some day, I'm going t have to try breaking stones with a sledge. We have a stone pile some 25 feet long by 10 feet high from when the septic system was dug.
Norm

    Bookmark   August 28, 2006 at 10:46PM
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js_ct

I've cut many chunks of granite, primarily for sidewalks, tho. Get several masonry chisels a good sledge hammer, and SAFETY GLASSES, score a line where you want to cut and just keep tapping all the way around until it splits. It takes patience until you get the hang of it.

    Bookmark   August 29, 2006 at 12:50AM
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maineman(z5a ME)

Baymee,

"I doubt that you can crack a rock embedded in the soil because it can't move sideways. You may need a blasting crew."

We live in town, so I think a blasting crew would draw some complaints from the neighbors and maybe bring a visit from our local police. Also, any flying pieces of rock could damage the house, because this worksite is fairly near to it.

We have partially excavated some of the rocks, so they do have some freedom of movement horizontally. I am thinking about trying some of the Dexpan® rock splitting material. It comes in three grades, depending on the temperature.

However, Dexpan® works best in holes that are at least 1½" in diameter, so I may need to get a more capable hammer drill than I had originally planned on.

I was planning on getting the Sears Craftsman Professional heavy duty ½-inch 7.8-amp hammer drill for $129.99. But now I'm wondering if that is suitable for drilling 1½" holes.

MM

    Bookmark   August 29, 2006 at 2:14PM
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baymee(LehighValleyPA)

Possibly, but how long will it last? Good used tools can be bought from Hamiltontools.com

I worked in mining in my younger days. Blasting crews know exactly what they are doing. We would sometimes get boulders stuck in the crusher chute and have to blast them to smaller pieces. One small piece of 3" or so of the modern equivelant of dynamite would reduce it to pebbles.

    Bookmark   August 29, 2006 at 4:02PM
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door

Site for ideas, wedge and feathers.

http://www.miconproducts.com/wedges.html

    Bookmark   September 2, 2006 at 11:33AM
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maineman(z5a ME)

Baymee,

I have no doubt that professional blasters have good control and can do a good job, but I don't consider that a desirable solution for our situation.

I have discovered that the Craftsman ½" hammer drill would be very insufficient for our rock drilling needs. I am now shopping for much larger and more expensive hammer drills with the capability of turning carbide bits as large as 1¾" and as long as 12" or more. I will do some drilling considerably smaller than that, but I do want to go as wide as 1¾ inches.

There are a bunch of drills available in this class, but my top candidate hammer drill at this moment is the Black & Decker/Dewalt #D25600K 11.5A 1-3/4" Rotary Hammer Drill. Northern tool has the D25600K for a little less money and free shipping.

Whatever I get, it's going to be a honkin' big drill. I'm currently shopping the Internet for 1¾" and smaller carbide drill bits. They're not cheap. I already have a 10-gauge 100-foot 3-wire extension cord.

MM

    Bookmark   September 2, 2006 at 3:21PM
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maineman(z5a ME)

Door,

Thanks for the Micon Products link. I may get some wedges and feathers from them, to compare them with the Dexpan.

MM

    Bookmark   September 2, 2006 at 3:28PM
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baymee(LehighValleyPA)

Try Hamiltontools.com for good used tools.

You only need small holes to split rock. They are about 3/4" in diameter and just a few inches deep.

    Bookmark   September 2, 2006 at 4:24PM
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dadgardens

Try using 'fingers and feathers - or wedges and feathers', they work better than dynamite on most stones. All you need to do is score a line with a chisel, drill small holes (in granite usually 3/8" about an inch and a half deep (use a masonary bit- tungsten carbide), insert the fingers/feathers and tap them in succession - works because of granite's friability (don't try it on conglomerates(usually purpilish matrix with pebbles included - they don't split, unless you use fire and water!). And; no I'm not a stone mason, I worked with one for two years in high school( that man(***) was probably a master).

The old technology really does work - often better than some of the new, for field work; or do it yourself work. Check a local stone yard for fingers and feathers; or wedges and fingers - they should have them - go there and ask, don't use the phone, you might be surprised.

    Bookmark   September 3, 2006 at 12:16AM
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maineman(z5a ME)

Baymee,

Dexpan needs holes in the 1½" to 2" range. You're right that wedges and feathers can use much smaller holes. I plan to take your advice and give the wedges and feathers method a try as well. A hole size of ¾" sounds like a good approach with the wedges and feathers.

But I'm proceeding with my original plan to try the Dexpan method. I ordered a Dewalt #D25600K 11.5A 1-3/4" Rotary Hammer Drill from Amazon because Northern Tool was going to take several weeks to ship it. I also ordered some Dexpan and a few masonry bits through Amazon.

MM

    Bookmark   September 3, 2006 at 12:38AM
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baymee(LehighValleyPA)

Let us know how it works.

    Bookmark   September 3, 2006 at 6:52AM
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andyma_gw

Last summer, my brothers and I met at my younger brother's cabin in the Adirondacks. One task we had was to chip off the top of a boulder that had appeared in the parking space. My older brother brought a few hammer drills and a 16lb hammer. We were getting no place fast until one of the neighbors showed up with this bar. It was about 6' long and had a tapered point on it. A few taps into holes drilled and the top of that rock split off flush with the ground.

    Bookmark   September 3, 2006 at 10:29AM
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masiman(z7 VA)

If you do go with a "drill" option, you would be much better served by an rotary hammer drill versus a hammer drill.

In the rotary, some well regarded brands are Bosch, Hilti and Hitachi. You can buy a cheap throwaway one from Harbor Freight. The SDS models are chucks and bit shanks that are designed to keep the bit from walking out of the chuck. More expensive but preferred in heavier applications.

    Bookmark   September 3, 2006 at 10:28PM
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maineman(z5a ME)

Masiman,

"In the rotary, some well regarded brands are Bosch, Hilti and Hitachi."

I saw a lot of Bosch models while I was doing online shopping, and a few Hitachi. I'm sure they are both excellent, if a bit pricey. I can't recall seeing a Hilti. I went with a Dewalt #D25600K 11.5A 1-3/4" Rotary Hammer Drill from Amazon, because I "saved" some money. Hope I don't come to regret that. But I do like doing business with Amazon.

"The SDS models are chucks and bit shanks that are designed to keep the bit from walking out of the chuck. More expensive but preferred in heavier applications."

Yes, I just learned about that during my current hammer-drill shopping adventure. I am still very new at this.

What I just learned yesterday is that SDS Max and SDS Plus (sometimes called just SDS) are two different chucks. My ordered drill has an SDS Max chuck (as most larger rotary hammer drills do), but before I became aware of the distinction, I ordered a big 1½" SDS Max bit (correct) and a set of smaller SDS Plus bits (incorrect).

I am pretty sure that the SDS Plus bits won't fit in the SDS Max chuck of my upcoming Dewalt. I will look for a converter chuck from SDS Max to SDS Plus so that I can use those smaller bits. Or just keep them until I get a smaller tool, possibly a cordless one, that accepts SDS Plus.

MM

    Bookmark   September 4, 2006 at 2:36PM
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masiman(z7 VA)

Well you are one up on me MM. I have never used one, only read about them :). The DeWalt was also mentioned and liked but the most praises and regard went to the Bosch Hole Hog and Hilti TE series. Hitachi was mentioned slightly more than DeWalt.

I did read about the different SDS chucks and conversions, but I did not "know" enough to comment on that. I hope there is a conversion chuck available for what you need.

I just got back from vacation in Bridgton. For the last 2 years as I have driven up there I have wondered if I was driving near your place. I saw a few raw lumber yards and many nice properties that looked like they had alot of work in them to maintain. Maybe one day I'll get to be a Mainer.

    Bookmark   September 5, 2006 at 8:40PM
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maineman(z5a ME)

Masiman,

"I hope there is a conversion chuck available for what you need."

Yes, I purchased the Milwaukee 48-03-3025 SDS-MAX To SDS+ Bit Adapter. A bit pricey at $70.96, but it lets me use a lot of less expensive SDS Plus bits.

"I just got back from vacation in Bridgton. For the last 2 years as I have driven up there I have wondered if I was driving near your place."

You weren't. We are up in the Augusta area. We're a lot closer to the ocean, and sea gulls make it inland this far to forage. Maybe one day I'll get to be a Mainer myself. I've only been here a little over four years and I still drive a "car" and not a "cah". (grin) The people around here think I am from the south, which isn't far wrong. We came here from St. Louis, but I worked in Texas for 20 years before getting a better job in Wichita. Y'all come to Maine, y'hear?

MM

    Bookmark   September 6, 2006 at 10:00AM
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shriner

I recently read this response to a similar query. Heat the stone with a torch along the line where you want it to split. When the area is hot, pour cold water on the heated area. Give the stone a few good wacks at the "treated" area and it will split there. It's a method that goes waaaaaaaaay back before Bosch days! But it apparently works as well now as it did for the ancient stone masons(go figure !)
WEAR APPROPRIATE EYE/FACE PROTECTION as you should with any method.

    Bookmark   September 27, 2006 at 10:55PM
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pjdbm

I know this job has been completed by now but I got to it late.

I have split over fifty thousand pounds of rock when I did a job on my house and all I needed was a Good mason chisel and a
five pound hammer. There is a way of spliting the most stuburn rock,yes it takes practice but it can be done. I did not need dimond blades nor jack hammers or rotary hammers. I split a hundred pound Marble boulder into five six inch thick pieces used for veneer. bA goog masons chisel runs about thirty dollars.

    Bookmark   October 1, 2006 at 1:00PM
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pjdbm

I forgot to add the statment about cost & ease these two will work AGAINST each other in any project. The cheapest way was the way I mentioned thats my way. You can also rent a 15 inch dimond blade gas saw and go to town on it.

Good luck

    Bookmark   October 1, 2006 at 1:09PM
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maineman(z5a ME)

Pjdbm,

Actually, the trench job is still in progress because I had some priority garden work that needed to be attended to.

I think marble must be easier to split than granite. Marble is a favorite of sculptors, because it less difficult to work with than other materials.

I don't need to split the one-hundred-pound and less boulders because we can and do lever them out and move them with a dolly. The granite boulders that remain in our trench are mostly in the 200 to 500 pound range. We encountered one boulder that is much larger, but it is deeper and we can ignore it as part of the bottom of the trench. Granite is denser, heavier, and harder than marble.

I think we can split the remaining rocks with Dexpan and wedges and shims into smaller pieces that we can wrestle with. We are using the resulting rock debris as fill material on a slope to extend the size of our garden.

I have had success splitting some fairly large granite rocks with wedges and shims and a 3-pound hand sledge. I think I'm going to prefer that method to the Dexpan, because it is relatively slow work drilling those deep 1½" diameter holes for the Dexpan. The wedges and shims require smaller, shallower holes that don't take so long to drill.

I have ordered a carbide 2½-inch "hand tracer" to score a shallow line on the granite to increase the effectiveness of my wedges and shims.

MM

    Bookmark   October 1, 2006 at 8:15PM
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pjdbm

Glad to hear you are making headway. I have worked with Granite,Marble and Crab Orchid and Limestone. Crab Orchid is really tuff to cut or drill, Masons hate working with these cause they eat up dimond bits faster than any other.

I find the grain,sometimes I have to wet the rock to find what I am looking for. I try to take a big rock like you mention in half,than I can make nice cuts off that piece I cut. My whole house is made of or surounded be Marble,Granite,Crab Orchid,Rainbow rock.

I love working with this stuff, I definately missed my calling but this is the way the cookie crumbled.

I also built a few walls,some cemented and some stacked. You can find a few good books on this stuff that you find very interesting. Stackable rock has a certain way to be installed for sturdyness.

Take care and good luck

    Bookmark   October 1, 2006 at 10:29PM
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patentnonsense(Dallas)

It's nice to hear from some experienced stonecutters - we don't have hard rock around here, but good stonework is a joy to see.

About rotary hammers though:
1) the "inch" ratings of the different manufacturers don't seem to be exactly comparable.
2) Besides Hilti and Bosch, consider Hitachi. Hilti is highly promoted and seems to be good quality, but their price seems to be even higher than their quality can justify.
3) The SDS-Max versions usually cost a little more than the "spline" versions, but SDS-Max bits are more interchangeable.
4) Straight demolition hammers ALSO use SDS-Max bits, and they wouldn't work for splitting holes, so read the product description carefully.

    Bookmark   October 5, 2006 at 5:53AM
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dadgardens

I just finished reading the thread (I posted earlier); but remembered two things.

You can split large rocks (granite etc) by building a fire next to them (charcoal is good) and then dousing them with cold water (induces fractures) and hitting them with a sledge hammer (Ukrainian/Georgian/Russian and many other groups) did it in the past(and present).

Or, you mentioned 500 pound weight range, you could move them with a chain hoist - and use the stones for your wall's base. Chain hoists used to be common items - for lifting engines out of cars (when shade tree mechanics were common).

You need a thick treelimb, or a moveable wood frame to support the weight (btw granite weighs a lot a chunk 3'x3'x3' is dang near a ton and a half in weight) I just ran the numbers and am feeling embarrassed - chain hoist won't work unless the boulder is about 2'x2'x2' (or smaller)- figuring in a safety factor - for a DIY'er (I do almost all of my work by myself - the old school way, may not work).

I learned what I know about stone, from an "old world master", wish I'd learned more, but only had two years under him; he moved on to help with a different project (St Patrick's in NY - or maybe another cathedral).Heck, it was the late sixties/early seventies.

Fingers and feathers work well, in my experience. They don't require high tech tools (which can help speed the process), but they work very well. Small holes + fingers/feathers = smaller granite rocks from large granite rocks.

    Bookmark   October 8, 2006 at 12:44AM
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