View Full Version : cutting granite

Andy Henriksen
01-20-2005, 8:54 AM
I posted this elsewhere on the web, but thought you guys might have some insight, too:

I recently got a piece of granite that I would like to use as a bar top in the basement. It's about 1.5 inches thick, and about 16" wide. it is finished (polished, or whatever) on the top and long sides, but the ends are rough and irregular. I need to crosscut them to square them up. I've seen a bunch of different masonry blades at the local big box store, ranging in price from 10 bucks to over 50. Is this the type of app these blades are made for?

I'm not to concerned about the ends being perfect, as I will probably band the whole thing with wood, but I would like to obviously avoid any chip out on the top surface.

Bart Sharp
01-20-2005, 11:41 AM
The cheap masonry blades will be fine if you're only planning on doing this once. I'm not much of an expert, but I did something similar with a piece of granite my wife wanted for a pastry board. As I understand it, the cheap blades (which is what I used) are like cutoff wheels, they do the job but wear away quickly. The more expensive blades (diamond?) last much longer.

Just watch out for the dust. That stuff makes a real mess.


Keith Outten
01-20-2005, 11:41 AM

I would try a diamond blade. The blades that are used in tile saws work well on most stone products and should do the trick. You must use plenty of water when cutting and take a very light cut across the top to minimize chipping of the top surface. I would look for an air tool to use since you must make some long cuts. An electric saw is always a problem when water is part of the equation. You can make a simple wooden sled and attach an air grinder which would get the job done safely.

Andy Henriksen
01-20-2005, 12:48 PM

You're saying to take multiple passes, all very shallow, rather than slowly chopping through the whole thing, right?

Keith Outten
01-20-2005, 2:17 PM

The first cut should always be shallow. Subsequent cuts can be as deep as your saw can handle. If you use a small air grinder shallow cuts will most likely be the only option due to the high RPM's and low power of most air tools.

Chris Padilla
01-20-2005, 4:32 PM
Some diamond blades can be used wet or dry but I think wet is preferable to help with cooling and lubrication and it also keeps the dust down. That said, I used a diamond blade from Home Depot ot cut up some slabs of sandstone (downright soft compared to granite of course) and I did it dry with no problems. They cut very cleanly and very nicely.

John Pollman
01-20-2005, 4:49 PM
Some good advice here but I've got another thought. Get the phonebook out and call some local stone shops. They may just square up the ends for you for a pretty reasonable amount. Just a thought.

Dan Mages
01-20-2005, 5:00 PM
When they installed my granite counters, they used a grinder with a diamond cutoff wheel. I hope this helps.


Keith Cope
01-20-2005, 8:02 PM

I think John is onto something there...a stone shop should be able to make those 2 cuts in a few minutes and likely won't charge as much as that diamond blade would cost you (and the mess is theirs to clean up!)--but, if you don't have one close, you can do it with diamond blades and patience. Use masking tape to define the line to cut to, it's much easier to see. If you end up with slightly rough edges you can knock them down with a sander. Good luck!


Scott Parks
01-20-2005, 8:31 PM
I've recently talked to a couple shops that charge about $10 per foot to edge granite. I don't remember if it was less than that to make a cut???

Chris Padilla
01-21-2005, 12:55 PM
I checked some shop's prices to cut up my slabs of sand/flag stone and while I don't recall the exact price, I decided to do it myself....

Edward Loughman
01-21-2005, 6:32 PM
If you don't have a side angle grinder ($55) - get one, since they are useful for so many grinding and cut-off tasks. Put a diamond blade on it and cut away. I install tile, stone etc. using the diamond blade dry. Rough edges can be polished but I usually edge with wood epoxied on and flush cut so water can run off and not get under the edge. Mask the cut line mainly as a guide but it does keep chipping minimal. Chipping is a function of how fast and how straight you keep the wheel to the surface. Don't worry, you will not mess it up. If you do, edge it with wood in an L shape with a raised lip (that will unfortunately trap water).