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This should be a simple question/answer for the ever-knowing TR forums gerbils. Girlfriend needs a compact angle grinder for her art studies. The biggest power-related requirement for it is that it should be able to cut marble and steel. So, what wattage should we be looking for? We're currently looking at Bosch 720-W and 1000 W units.

No idea the answer, but uh...sleep with one eye open.

If only angle grinders were powered by smartassery...

The best news about this thread is that the German for "angle grinder" is "winkelschleifer" which is a fantastic word.

Either of those will work, but definitely focus on the blade. Diamond blade with a continuous edge rather than one of those notched ones (should make a smoother cut/line).

DancinJack wrote:

Either of those will work, but definitely focus on the blade. Diamond blade with a continuous edge rather than one of those notched ones (should make a smoother cut/line).

You also want to make sure the blade is durable as well. Diamond blade should last, but if you don't get one that is coarse enough it could grind down way too quickly, especially on steel and marble which I have never actually tried, although I did grind on steel, but it was to get paint off.

Since you're looking at handheld tools I'm assuming you'll be cutting relatively thin sheets or tiles instead of big, heavy slabs. The 1000W grinder you linked should probably be fine for cutting marble with a decent cutoff wheel. Anything more powerful than that would make me nervous. I don't have much experience working with steel, but I know there's a big difference between working with mild steel and something harder like tool steel.

Get some ear protection and a half-face respirator while you're at it if you don't already have them.

For what it's worth, the marble work will be more sculpting tiles / blocks than outright cutting them.

morphine wrote:

For what it's worth, the marble work will be more sculpting tiles / blocks than outright cutting them.

Well, the 720 appears to have more of the disc surface exposed (assuming she doesn't just remove the shield), which may come in handy in sculpting/shaping uses. The 720 would also (handwave here) make it more difficult to take too much off too quickly.

absolutely get the mask and some gloves and glasses as well. You will need them for sure.

If carving/shaping marble is anything like my experiences doing power carving in the woodshop, then the dust and stuff is going to get everywhere, but that's just part of the fun.

It will. Do it outside if you can, or in a garage or something. If you do it in the house/apt you will be finding dusty surfaces months later.

Marble, I have no idea at all, but steel and angle grinders-40 years +.
I'd say-get the 1000 watt one. Hope she has strong hands and wrists,
angle grinders are not nice.............
Just checked my 5" Bosch-900 watt, the label on my Metabo has worn off.

From experience in the steel industry-Metabo, Bosch and Hitachi are the brands that last.
But saying that, a friend in the brick and stone industry, has stopped buying the good brands,
he reckons the dust kills them just as fast as the cheapies, so he just buys the Chinese ones now,
he burns about three a year.

HERETIC wrote:

angle grinders are not nice.............

Indeed. As I said my only experience using an angle grinder is in wood with power carving, but there have been a few times where I've tweaked it and had the blade dig in. Fortunately I don't have much trouble keeping control of the tool, but since I was new to the process and the work piece wasn't secured in some way that meant launching a 10-15 pound chunk of wood a few feet through the air. My cheapo little 600-ish watt grinder seemed to have no problem doing that.

Redocbew wrote:

HERETIC wrote:

angle grinders are not nice.............

Indeed. As I said my only experience using an angle grinder is in wood with power carving, but there have been a few times where I've tweaked it and had the blade dig in. Fortunately I don't have much trouble keeping control of the tool, but since I was new to the process and the work piece wasn't secured in some way that meant launching a 10-15 pound chunk of wood a few feet through the air. My cheapo little 600-ish watt grinder seemed to have no problem doing that.

If you ever get a chance-fire up a 9" with a new 6mm disc.
It's got a decent kick, before you even start doing any work...............................

Consider something like this:

https://www.stihl.com/STIHL-power-tools ... e-saw.aspx

Advantages - no dust and easy to handle with no angular momentum issues to deal with. Sounds great and makes you feel good.

I've never done work with stone, but on steel the higher wattages only come in handy when you're really beating on the material. I own a 1200 watt Hitachi, and a 600 watt cheapo unit from Harbor Freight, and 90% of the time I prefer the cheap unit because it's like 3x lighter than the Hitachi, and I don't think I've ever stalled either unit, although the little one does get quite hot when I push it hard.

The weight difference between the two linked Bosch units isn't much (100g), so IMO it comes down to design and aesthetics like the positioning of the switch. All of the Metabo and Bosch units have the tiny click over switches, whereas some of the "American" brands have triggers much further down the handle (like this one), which might be more pleasant for long sessions. I can't find any of them on the German Amazon though.

Definitely think about dust collection and removal because stone dust can be super terrible for your lungs. Maybe even something like this if she's doing mostly flat grinding work.

Pancake wrote:

Consider something like this:

https://www.stihl.com/STIHL-power-tools ... e-saw.aspx

Advantages - no dust and easy to handle with no angular momentum issues to deal with. Sounds great and makes you feel good.

Eh, not sure where you're getting the no dust thing... if you're cutting marble you're getting dust.

Also, if she's doing artwork - sculpting and such - she's gonna want the control that an angle grinder will offer (relatively speaking) over a chainsaw.

To echo what others have said... she needs to do this outdoors if possible, with good eye protection, ear protection and a mask; stone dust is seriously bad for your health.

derFunkenstein wrote:

No idea the answer, but uh...sleep with one eye open.

These pajamas would be something to buy as well.

In all seriousness, this is the kind of thing i'd buy locally from somewhere with a good return policy, in case you actually need to try a couple out.
I'd also look into renting or borrowing to let her try it out at home prior to purchase.
Lastly, besides mentioned "mask and some gloves and glasses," remind her to put her hair up/wear a hat, and long sleeve clothing/overalls.........just makes it easier when cleaning up.

I'm with Superspy. Both wattages will to the trick. Obviously higher wattage will let you get more aggressive, but more power generally comes at the cost of more tool weight.
Also, too high of wattage can become unsafe depending on the physique of the user. Sometimes it's nice to know you can overpower the tool you're holding in the event of a mishap, instead of it ripping your arms off. You might not set any speed records this way, but you'll live to fight another day.

I second the vote for the smallest and lightest tool that will do the job - especially for sculpting / art. The angles she'll be using it at will be very different than the typical uses of such tools. Good blades and maneuverability will matter far more than the motor power.

EDIT: Also, PPE is a must! Goggles (sealed preferably), face mask rated for such small dust, gloves/arm guards, work boots, etc. Even smaller grinders can do damage extremely quickly in certain situations.

Yeah, definitely get sealed goggles if you can find some that don't interfere too much with the respirator. It's really annoying when airborne dust or small chips find their way up and under safety glasses.

A full face shield can be an alternative also. I often wear one of those while working at the lathe, because that can also send little chips flying and make quite a mess.

DPete27 wrote:

... but you'll live to fight another day.

Exactly. I have a Bosch AG40-85P 4-1/2-Inch Angle Grinder (120V, 8.5A) and it's pretty jumpy with new cutting wheels.

1000+W in a little 4.5" blade is pretty touchy at times

Had to look when I got home. My Milwaukee is a 1200W.

Biggest concern to me is weight, especially in situations like this where she may not be grinding in a consistent and comfortable position. A lighter tool can drastically reduce arm fatigue. A pound makes all the difference. The more "industrial" quality tools may be built better, but they can also be heavier as a result. Like others have said, for very dusty situations like this, the dust might negate the quality of the tool.

And yes, as with any cutting/grinding tool, having the right "blade" of good quality (and sharp if applicable) can be the difference between effortless and hard work.

With angle grinders, use the screw-on handle if at all possible.

cphite wrote:

Pancake wrote:

Consider something like this:

https://www.stihl.com/STIHL-power-tools ... e-saw.aspx

Advantages - no dust and easy to handle with no angular momentum issues to deal with. Sounds great and makes you feel good.

Eh, not sure where you're getting the no dust thing... if you're cutting marble you're getting dust.

Not with water. You get glorious mud. I cut rock, bricks, tiles and concrete for a living and have a lovely assortment of concrete saws, table saws, demolition saws etc. Water makes it all good and you can keep going all day. You can't do much with an angle grinder even outside without annoying your neighbours. One gust of wind and the clothes they've hung out are covered in dust. Or their windows. Not cool.

Thanks for your input, guys! Since my girlfriend is small, we opted to go with the Bosch 720W unit. We'll be looking at protective gear now.