Best angle grinder blade for cutting granite?

[Joanne29]

Hi,
I have an angle grinder that takes a 9" blade. I wondered if anybody could recommend the best blade for cutting granite. I have a fair bit to cut. I've read a few things about the best blades but find myself even more confused. Obviously I need a diamond blade, but there still seems to be so many of them and some apparently are more likely to cause chipping to the edges than others? Confused!?
Any recommendations much appreciated.
Thanks very much

(*Edited my original post where I called my angle grinder a circular saw if the responses don't make sense thereafter!)

 

[Deleted member 174758]

A standard wood or metal toothed blade cannot do this job. Instead you need a something like a segmented diamond cutting disc (sometimes called a diamond saw), more akin to an angle grinder cutting wheel than a saw blade. Because granite is very hard, you need a cutting wheel with a softer bond so that fresh cutting surfaces are constantly exposed (meaning the wheel stays sharp and doesn't clog). I have dry cut granite worktops with a 9in angle grinder, so I can confirm this works

The main difficulty I can see is that most of these discs in 230mm diameter are made with a 22.2mm bore to suit angle grinders, not the more normal 30mm you'll find on a modern portable saw. Another potential problem is that a circular saw is just a bit slow (rpm) for the task

 

[Notch7]

Sounds like a recipe for a terrible kickback.

 

[Joanne29]

God shows my ignorance!! It's not even a circular saw I have, it actually IS an angle grinder! ‍ (for some reason I thought an angle grinder was just the one that takes smaller discs!) ‍ ....Anyway! Sorry and thank you for your reply. Sorry if I've wasted your time not even knowing what I'm talking about in the first place! This is what I have.... (see pic) and I will have a look for what you advised. Thanks very much

 

[Joanne29]

Sounds like a recipe for a terrible kickback.

Do you mean because I said I was using a circular saw? I realised it is actually an angle grinder and I just don't even know what the thing is called!! Cringe! Or another reason? Thanks

 

[Mr Chibs]

If you are cutting down a long worktop, then even the cheaper erbauer discs from Screwfix, will cut granite/quartz.

Diamond discs

I recently cut some using a small angle grinder, please wear a mask, googles, ear defenders, hat, gloves etc... it's very dusty.

 

[catlad]

If you look on the bosch professional website, on the diamond disk section there is a guide to what disks are best for what materials, they also have a rating of 1-2 and 3 diamonds for best quality. 3 being the best and most expensive!

 

[Mike13]

The segmented blades are meant mostly for using dry, and the continuous edge blades are mostly for wet cutting, but if you do not have a special cutting table for that I can imaging a lot of mess when cutting wet. Diamond blades work best at a higher speed and a lower cutting pressure than carbide blades. I recently bought some 115mm blades for cutting sandstone paving slabs and can safely say it is very dusty and noisy. If you let the blade take its time you can keep the edge mostly sharp, but if the surface gets too hot it will spall off as little fragments.
Aldi currently has sets of 4 blades 125mm diameter for £5, so quite a good deal, 2 of each type. You cant cut deep with that, but if it is only worktop you should be ok to cut through.

 

[Joanne29]

If you are cutting down a long worktop, then even the cheaper erbauer discs from Screwfix, will cut granite/quartz.

Diamond discs

I recently cut some using a small angle grinder, please wear a mask, googles, ear defenders, hat, gloves etc... it's very dusty.

Thanks, I saw these in screwfix, but I guess because they are cheap I wondered if they would be any good. But I've just ordered one to try, so thank you.

 

[Joanne29]

If you look on the bosch professional website, on the diamond disk section there is a guide to what disks are best for what materials, they also have a rating of 1-2 and 3 diamonds for best quality. 3 being the best and most expensive!

Thanks, never looked on their website! That's really useful info. I'll probably order one to try. I've a mountain of granite and marble I'd like to 'play' with so to speak, so I'm bound to mash up a few blades in the process. The more help I can get via decent gear, the more chance I have of not destroying things too much with my lack if skills! Fingers crossed!

 

[scbk]

If you've got much to cut, might be worth looking at getting a cut off saw with water suppression? The dust is nasty stuff

 

[foxhole]

I used a basic tile cutting blade on my grinder, cut granite with ease .
Used a belt sander to smooth cut edges .

 

[opps]

How thick is the granite, and how many metres do you need to cut?

How precise do the cuts need to be?

How important is the quality of the edge?

 

[opps]

I used a basic tile cutting blade on my grinder, cut granite with ease .
Used a belt sander to smooth cut edges .

Which belts did you use to smooth the edges? Off the top of my head, I really cannot think of any that will not become blunt after minutes. That said, I have never tried zirconium belts on granite.