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Cutting a 6" thick granite surface plate?

richard newman

Titanium
Joined
Jul 28, 2006
Location
rochester, ny
I've been watching locally for an old 3' x 4' granite plate to use as a reference flat for building a small, precise cnc router. Just saw a 55" x 65" x 6" plate on craigslist cheap, but it's on the ground and the guy no longer has a way to lift it, nor do I. If I cut it into 2 pieces it gets much more manageable, and maybe someone else can use the other piece.

So, is there a reasonable way to cut thru 6" granite? I have a worms drive Skilsaw, it's a beast, but will only cut 3" max. We could probably figure a way to flip it over. Any suggestions for a guy on a low budget?
 
Aggressive diamond blade for masonry, a water hose, a properly set up GFCI outlet (and heavy rubber boots), cut one side, use wedges to split.

Or be a proper quarryman, get some nice explosives, drill a couple holes and blast that puppy!
 
I've been watching locally for an old 3' x 4' granite plate to use as a reference flat for building a small, precise cnc router. Just saw a 55" x 65" x 6" plate on craigslist cheap, but it's on the ground and the guy no longer has a way to lift it, nor do I. If I cut it into 2 pieces it gets much more manageable, and maybe someone else can use the other piece.

So, is there a reasonable way to cut thru 6" granite? I have a worms drive Skilsaw, it's a beast, but will only cut 3" max. We could probably figure a way to flip it over. Any suggestions for a guy on a low budget?

.
call place that does granite kitchen countertops. they probably have equipment to cut it and you can ask how much for cut. by the way heavy stuff it takes time and labor to even move around. not like a person can pick it up. you talking a fork truck to load and unload
 
About 2110# on the ground? A shovel, engine hoist, pry bar and some rigging/cribbing should place that on your trailer no problem.

Or you could always call a wrecker, that's my go-to for stuff like this.

Once at home, use the worm drive saw and a fence to begin a slot with a diamond wheel then take it to depth with a quickie saw. Would have to approach from both top and bottom though.
 
i REALLY want to see look on the kitchen granite shop guys face when you ask if they can handle a 65" x 55" x 6" thick slab.

after the look of bewilderment on his face fades and he collects himself,I want to see the look on yours when he says "sure,bring it on in" :)
 
definitely just get some straps under each corner even if you need to dig in the dirt to do it, then a tow truck fork lift to lift it and set it on some cribbing on your trailer/ truck.

you cant pick up either piece without a forklift / tow truck anyway.

Cut it later rather than where it sits.

Having a beastly table doesn't help a cnc router much as all the flex and vibration is usually in the bridge. I would rethink your plan.
 
i REALLY want to see look on the kitchen granite shop guys face when you ask if they can handle a 65" x 55" x 6" thick slab.

after the look of bewilderment on his face fades and he collects himself,I want to see the look on yours when he says "sure,bring it on in" :)

.
many have waterjet cutters and often cutting 2" or 6" not much different other than going slower
 
This would not be part of the router, just a flat reference surface to assemble on with for maximum precision, using indicators.

In halves, we could probably wrangle it onto a pallet on a hyd tailgate rental truck. Easier to unload at the dock too. Levers and blocks, the old ways.
 
Too big for countertop fabricators, you want a monument shop, which is what does gravestones and such. They ain't going to be the cheap way to do it though. That is a Skill saw with a diamond blade, get one that is for granite, 7" with a diamond cutout is not rare, garden hose and cut as deep as you can on BOTH sides before breaking it for best control. Levering it on a board would be better than wedges IMO.

Wood plugs in the drilled holes then watering them to make them swell is how the good quarymen would do it, much less damage to the blocks that way.
 
Oh leave it full size if you have the room. The cut side will never be pretty and the extra piece is going to be worthless unless you already have someone that wants it.
 
I have a dimensional stone business, 6" is thin for us, Milland is sort of right, hey he's a granite stater - we sometimes use a worm drive saw with water feed & GFCI to cut stone on site - a decent quality turbo diamond blade and water will cut as deep as saw cutting depth will allow, but should be done in steps - then flip the plate and repeat - also the stone can be broken off if you cut 1/3 of the way through, put the cut on a raised straight edge and wack and end with a 3 lb hammer, using a block of wood to save stone from the blow of the hammer - the deeper the cut the cleaner the break, but in any case will break unevenly if snapped - DO NOT FORGET TO USE A GROUND FAULT INTERUPTER
 
Cole is correct on weight - it is 1900 to 2400 lbs depending on what variety of granite it is
 
The smaller the steps the faster you can feed and the easier it will be on the blade. Start with 1/2" and work your way up. If the blade quits cutting you can dress it with an abrasive wheel on an angle grinder, like used to clean up welds, held at a 45 degree angle to the sawblade. With both running dress the face of the saw blade square. Works fast and will make it cut like new if done right.

Oh, and cover the foot of the skill saw with blue painters tape to reduce scratching up the stone. OH OH the blade will cut best climb cutting, the blade won't grab that much. Treat it like a form grinding wheel for best results.

GFCI is nice but depends on your tolerance of electrocution. Water should be on the saw blade not on the motor.
 
Thick granite can also be split with a series of holes in a line (think rotary hammer drill) into which you've inserted three-piece wedges and shims. Flechetts, I think I've heard stonemasons refer to them. There was a This Old House episode from the early 90's where Steve Thomas used them to split a granite step. I believe Amazon even sells the wedges in sets.
 
Skilsaw might not have the rpms necessary to cut the granite efficiently. If you are really inclined to DIY, I would recommend renting a gas powered concrete saw with a big enough blade, will save you lots of headaches.
 
Skillsaw will do perfectly fine, done plenty of this myself cutting 2 and 3 cm slab that was too big for my tile saw. But cutting stone is NOT what it was designed for so renting one would save yours from the carnage. Kinda like grinding on the lathe, not the best idea for longevity.

You're looking for 4-5000 sfm for reference, if you were doing production. A little slow won't hurt anything, a little fast and the blade won't like it.
 
too bad your not closer, Granite guys that used to be behind our shop had a saw that would cut it like butter. Most of the Granite counter top guys here in AZ have big saws that are semi cnc.
the blades are about 20-24 inchs dia table runs about 8-10 feet x 8-10 feet tilts up to 90º and angle in any direction.
keep checking with the counter top people someone in your area has a saw that would be no problem. if that doesnt pan out check with the companies that sell granite to them they'll always know people who has one, no to mention they might come and pick it up take it to them and get it cut.(of coarse for a fee)
 








 
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