6-7" angle grinder

[ATC]

I'm looking for a larger grinder for cutting and grinding....maybe some wire wheel use too. I have about Five 4.5" grinders...but never really looked into the larger ones. But I'm doing some projects here lately that would make it nice to have. Realistically, I would only use it a few times a year. Would a nicer name brand grinder be worth the 3-4x price premium (Makita, Metabo), or does anyone have a Bauer (Hercules) they could give a review on? I only ask because the Bauer is on sale right now. With my infrequent hobby use, I thought it might fit the bill unless it's junk.

I also hear there is quite a bit of difference between a 6" grinder and a 7"...mostly in weight. Again, I've never really looked into these larger ones or done any research on them until right now.

 

[Hal]

Go ahead and abuse yourself. Get a nine inch!
Doesn’t weigh a lot more than a seven, and you can really remove some metal with it.
I think that with the bigger machine, a brand name may be lighter, more powerful, and longer lived.
For a long time my nine inch B&D was the only grinder I had, moving to a four and a half was such a relief, but I still pull out the big one for serious grinding.

 

[john.k]

Be aware that big grinders have a powerful gyro effect .........also powerful potential for damage if a wheel busts .......the old Makitas the 7" was a 9" with smaller guards .......unbustable ....................also you must never use a 14" cutting disc in a 9" grinder

 

[GeoBruin]

I have a dewalt rat tail 7" I've used for some time. Subsequently, I picked up a Hercules dust shroud on sale at HF because I had a bunch of concrete grinding to do. Turns out, even with all the adapters, there was no reliable way to make the shroud fit my dewalt. Then the Hercules grinder went on sale and I figured "hey, one can't have too many grinders" so I picked one up and used the **** out of it on my concrete project.

It survived the ordeal and and now has a flap wheel permanently attached. I have no complaints, other than it seems heavy.

I know they make a 15 amp Bauer with a rotating 3-position head that looked interesting. Is that the one on sale?

Edit: I just saw your picture. That is the one on sale. Assuming it doesn't introduce reliability issues, that rotating head seems cool. It would be nice to have the trigger in a normal orientation when switching from grinding to cutting.

 

[cgrutt]

I bought a 7" Bosch for a project where I needed to grind a portion of concrete slab with a diamond wheel. I have also used it with a large sanding disc and metal cutoff wheel. Don't recall ever seeing a wire cup for 7". It's significantly more "torquey" than a 4" so use whatever you get with caution.

I also have a Makita buffer which is about the same size. The Makita is very nice and has a slow start feature but I'm not sure if they include that with their grinders or not.

There is nothing wrong with the Bosch but I'd probably look into Makita if I had to buy again. With that said I'm sure any of the known brands would work fine.

 

[NUTTSGT]

I bought a 7" grinder from HF. It's the older "brand" that is purplish in color. It's whole reason for existence is for cutting concrete blocks. It's done that quite well.

Would I spend big money on a real good one to use a few times a year ? Probably not, but if you caught one on sale. . .

 

[tarbellb]

7" vs 6" BIG jump in size and weight

I imagine the Bauer is probably fine, all the big dog grinders are brutes. If you're grinding concrete the Bauer dust shroud works very well and even allowed me to rest the shroud on the ground and control the grind really easily.

If you aren't in a hurry these big grinders are all over the used market

 

[Roert42]

Even a 5" grinder is a nice upgrade from a 4.5"

Little more power, little more weight to help with heavy grinding.


I've 9" DeWalt (has a guard for 7" and 9") that I rarely use since I don't do a lot of heavy metal fab at the moment. Mostly use it when I want to off an exhaust, 9" wafer wheel can lop a 3" pipe in one go.


If you want a bigger grinder, but a 5" Makita rat tail with a trigger. Save the 7" or 9" until you need to spend all day grinding on 1" plate or something.

 

[Dave455]

I must admit, grinders are one of the few tools that have the ability to scare me.

I bought a cheap 4 1/2” once for one job, and never again. It was quite the nastiest power tool I’ve ever owned. Felt rough as anything to use, even with a good disc. The noise level was horrific (my ears rang even using ear defenders) and the awkwardly placed switch stuck in the “on“ position.

No way would I go cheap on a bigger grinder.

Those suggesting a 5 inch grinder are sensible. I have 4 1/2 and 5 inch and the 5 inch feels like more of an upgrade than the numbers suggest.

Wire wheeling is probably the exception. For use on a 4 1/2 or 5 inch grinder you are probably going to be stuck with a 65mm (maybe 80mm) cup brush, due to the speed rating on the brush.

A slower 6 inch grinder will generally allow you to use a 100mm brush, which will shift an awful lot more.

 

[dnschmidt]

Grinder = METABO Not Metabo HPT. The real deal from Germany

 

[Maui]

I purchased one of those big angle grinders at an auction years ago for very little. It is much heavier than my 4 1/2" angle grinders and works great. It has a frightening amount of power. To this day I've never had a need to use it. But I one day I hope I will.

 

[tarmy]

I have lots of 4.5 and a 5, 6, 7 and 9 inch grinder as I like to do metal work. I try to never pull that 9 out unless I really need to. There is gonna be some hard work involved in horsing that thing around for any period of time. Nothing beats a good grinder that has some beef to it for removing material.

I made a shroud for the 9 that allows a 10” diamond saw for concrete work…and have it hooked up to my shop vac to keep the dust somewhat under control…

 

[Vinny]

Don't skirtsafety with bigger grinders. One of my worst incidents was having a big disc explode while using a gas powered grinder to cut large girders. Luckily I had a full face 3M respirator on, as bits of the disc embedded in it. Without it, I might not have made it. Turned my leather apron to Swiss cheese.

 

[whateg01]

You do you, but I bought a 7" thinking it would be nice to remove more metal faster. It does that. But it's so heavy compared to the 5" that I almost never use it.

 

[u2slow]

I have the 7" Makita that is based on the 9". Faster gear ratio and guard size are the difference. It has a 15A plug but needs a 20A circuit or it trips with any load.

It makes brisk work of cutting up truck frames (for example). Doesn't bog down like a 5" does. When the 7" discs wear down some, they last really well in the 5" grinder.

Edit: was model GA7062 from Amazon for $120CAD a couple years ago.

 

[finn]

I have a Craftsman Professional 7” grinder that I think was a relabeled B&D made before the Dewalt brand became SBD’s premium brand and B&D was relegated to the “homeowner bargain line”.

The thing frankly scares me, and I probably haven’t used it in twenty years. It’s too powerful and, from what I remember, could rip itself out of your hands if you don’t pay attention.

I have at least a half dozen 4 1/2” grinders and a 4”. I wouldn’t buy another 7”, let alone a 9” .

If, for some reason, I had to buy a larger grinder, I would seek one out that has an electronic brake to stop the spinning disc, if such a thing exists.

 

[LopezBart]

I used to have a large grinder back in the 70-80s; it disappeared during a move, sigh. For working downhand, it was fine and certainly fast at cleaning up a welding table, for example. I would hesitate to use one w/ a cut-off wheel - it's too easy to twist when working up in the air. I use a 14" cut-off saw if I can clamp/secure the part.

If I were building a steel boat or large trailers, I'd have one. Failing that, I find my 5" M18 angle head enough for now, although I've not yet used it on a larger project.

 

[Beerhippie]

Do you have the wiring to support a big grinder? We used a large--10"?--15A rated P-C years ago when we were building out the brewery. The thing would pop a 20A breaker about every third time we'd start it.

 

[charbar]

The thought of something like that from Harbor Freight scares me I have found most things from Harbor Freight that run off electricity are rather underwhelming and then they die. But I have no experience with that particular grinder either so I'm just basing that off my personal experience with other things they offer.

I've got a 7" Makita that is every bit of 30 years old and has never skipped a beat and has way more than enough power to chop through your torso if you aren't paying attention.

 

[Steve_P]

You do you, but I bought a 7" thinking it would be nice to remove more metal faster. It does that. But it's so heavy compared to the 5" that I almost never use it.

I have an old B&D 7" from my dad - I'd guess ~40 years old. It is an absolute beast and has almost enough power to slow the earth's rotation. I haven't used it in years- I'll stick with my 5" (German) Metabos, with the anti-vibration handle, that probably weigh half as much; I'll work a little longer as that's a fair tradeoff IMO. If you're working on heavy equipment for pay, then time is money, go big. Otherwise, I'd rather take a little more time and not feel like I've been beaten to **** when I get up the next morning

 

[no704]

I’ve got an older HF 9” with diamond disk I’ve used a few times cutting concrete. Probably been thru about 75 liniar feet. Haven’t killed it yet.

 

[GaryM909]

I pretty much use 6" grinders exclusively but for a project I am working on now I am using my 7-9" Makita with a 9" fibre disc on it. I can flatten the welds nicely and the grinding marks don't show.

 

[fourjeepin]

I too have an older HF 9”. I bought it probably 12 years ago to cut foundation vents in my house but have ended up using it about every other year for a concrete project.

As others have mentioned, super heavy and rather scary to use. But it will move some material plus has much better cutting depth than a 4-1/2”

 

[john.k]

Its worth buying a quality grinder ,cause unlike batteries ,mains power wont change in your lifetime. and yes a 7 or 9 grinder will be heavy and powerful .....thats what you bought it for..............i still have big Makitas bought 50 years ago ...............one thing I ve seen kill big grinders is cutting large dia plastic pipe using a portable genset as power.

 

[MOS3522]

I prefer the Dewalt Flexvolt 4.5-6" one over the larger sizes. It's much easier to control and still eats material. But pricey with two batterie$.

 

[john.k]

Air grinders are a revellation ...light ,powerful,cool running ,stop almost instantly you release the trigger ........catch being the 50-70cfm of air needed......i had a 7" Atlas Copco disc grinder ,it used the worn discs from the 14" cutoff saw ...thing was absolutely magic.

 

[IndyGarage]

I have a big 7 inch Hitachi (would now be Metabo HTP) a big Makita all-metal 7-9 inch and then the big mother of all grinders - a Dewalt 9 inch.

They all run great, but the Hitachi is about the biggest and most powerful I can handle for very long. The Makita just has a ton of power, and the Dewalt is insane. I have an 8 inch cup wheel on the Dewalt and literally my wrists give out in about 5 minutes. If I have a very big wire brush job I'll pull it out, otherwise it stays on the shelf.

Run one of the big ones for awhile and those 4 1/2 inch grinders seem like a toy.

 

[john.k]

If you weld thicker than 1/4 steel ,then you need a 9" grinder ..simple as that.................anything smaller is wasting time.

 

[MOS3522]

and the Dewalt is insane

That's what made me go back to the 6" model. I couldn't work with this sucker for more than ten minutes and it was all over the workpiece because I could barely hold it.

 

[joe_padavano]

I've had the Dewalt 7" for decades. Done a lot of sanding and grinding with it. Zero issues. Never missed a beat.

 

[driftpin]

When I need something big/heavy, I use a Milwaukee corded 9" and I'm surprised that one hasn't been mentioned. I have two of 'em including one I bought at a yard sale where I also got a fiberglass 24' extension ladder. My most recent use was to scrape-off terrazzo sealant from the laundry floor of a 60+ year-old SFR (single family residence),I used a red abrasive pad, one of those which looks like a coarse sponge. My rest breaks were longer than the work times, but it cut through the layers of sealer on the terrazzo better than a wire cup did. What was once a somewhat transparent grey build-up is now white terrazzo. The rear door from the laundry opened to the outside, and a door from the kitchen to the laundry was on the opposite wall. I used a 15" floor fan to direct the airborne sanded debris out the rear door, but I also had to change the air filter on the AC because of the build-up of airborne sanded material.

 

[Nutria]

I have an old B&D 7" from my dad - I'd guess ~40 years old. It is an absolute beast and has almost enough power to slow the earth's rotation.

Ha! Yes. And good luck finding a shield. But strong and indestructible.

 

[GaryM909]

Ha! Yes. And good luck finding a shield. But strong and indestructible.

I have one of those. Last time I used it was over 15 years ago. I put a flap wheel on it and used it to remove the stain on my deck. I bought it back in 1981. Now it’s hiding deep in the back of one of my cabinets.

 

[LopezBart]

Air grinders are a revellation ...light ,powerful,cool running ,stop almost instantly you release the trigger ........catch being the 50-70cfm of air needed......i had a 7" Atlas Copco disc grinder ,it used the worn discs from the 14" cutoff saw ...thing was absolutely magic.

Back in the 1980s, watching them do rework on BFV aluminum turret welds with an air-powered circular saw sporting a 3/4" wide carbide milling cutter at the old FMC plant next to San Jose Airport was pretty amazing. Big fat air hoses.... I was told that this was the area w/ the most worker injuries, unsurprisingly.

 

[Beerhippie]

Back in the 1980s, watching them do rework on BFV aluminum turret welds with an air-powered circular saw sporting a 3/4" wide carbide milling cutter at the old FMC plant next to San Jose Airport was pretty amazing. Big fat air hoses.... I was told that this was the area w/ the most worker injuries, unsurprisingly.

That's... terrifying!

Almost as scary as those chainsaw-tooth disks for sold for "woodcarving" with 4 1/2" angle grinders.



I mean, what could possibly go wrong with that spinning at 11,000 rpm? I'm amazed they're still for sale.

 

[no704]

That's... terrifying!

Almost as scary as those chainsaw-tooth disks for sold for "woodcarving" with 4 1/2" angle grinders.



I mean, what could possibly go wrong with that spinning at 11,000 rpm? I'm amazed they're still for sale.

I’ve got one of those. Still in the package, I’m afraid of it!

 

[Wamsutta]

I could really use a 9-inch grinder for the cutoff wheel. Disassembling welded T-joints is what I'd use it for.

 

[ATC]

Thanks for all the replies....I promise I didn't forget about ya, but I chock it up to poor timing starting this thread with Thanksgiving sneaking up on me! Haha

I am doing more heavy metalwork where having a larger grinder would be nice. I had to grind a bevel in a 3/8" thick piece of 2x6 which was not enjoyable with a 4.5". Didn't feel like dragging out the plasma or torches though. I had to cut some angle iron last week (attached to a larger structure), so I had to flip it a couple times so my 4.5" could reach. A larger grinder would have done it in one pass without having to move the piece. I have a project in the near future involving cutting a truck frame and modifying it too.
No concrete work...but it would be nice to be able to cut pavers or brick for the odd job here and there.

I think a 6" would be nicer to use, but I'm not afraid to wield a 7" for the infrequent use I would have for it. I'll keep an eye out on FB marketplace, and scout out the tool deals on BF/CM this weekend.

 

[ATC]

Do you have the wiring to support a big grinder? We used a large--10"?--15A rated P-C years ago when we were building out the brewery. The thing would pop a 20A breaker about every third time we'd start it.

I should. Breaker panel is only a few feet from where I will be using it 90% of the time, with a couple dedicated circuits right there. 15A breaker, but can upgrade it to/add a 20A easily.

 

[Beerhippie]

I should. Breaker panel is only a few feet from where I will be using it 90% of the time, with a couple dedicated circuits right there. 15A breaker, but can upgrade it to/add a 20A easily.

Don't forget to upgrade the wiring to 12 AWG, too. 15A breaker usually uses 14AWG.

If you're welding a lot of heavy metal, esp. plate, look into a dedicated bevel grinder. It'll make your life more pleasant and your welds more uniform. I don't own one, but a friend lent me one when we were building out the brewery and doing a lot of heavy metal.