electric angle grinder vs air grinder

[danski26]

I'm trying to decide between a milwaukee angle grinder or a pnumatic grinder. I'll be using it for welding and other general metal work. Any opinions wich works better?

[carpetman]

danski---I think the electric would be efficient enough without the hassle of having to run a compressor for the pneumatic.

[2400]

I'm trying to decide between a milwaukee angle grinder or a pnumatic grinder. I'll be using it for welding and other general metal work. Any opinions wich works better?

I've got both kinds of grinders, for welding I'd use the electric grinder. I've got 4 Milwaukee's, they're money well spent. When you buy one look at the plate on it and make sure that you have the 8.5 amp or 12 amp version, the 5.5 will not do what you want. When you buy either hard grinding discs or the flex discs get a good name brand (Sait or Norton) not the cheap crap at the discount store. If you have any questions PM me, I'd be happy to help if I can.

[grumpy one]

In my limited experience it depends what you will use it for. Air grinders tend to be considerably lighter and handier, so very small ones are extremely useful for things like die finishing - true one-hand tools. At the other extreme I used to have a ten inch angle grinder that had a three-phase induction motor instead of the usual commutator motor. That thing was a bit of a chore to use for long periods. Generally, as the grinder gets bigger the weight disadvantage of electric over air gets less important. So long as you are looking for a two-handed tool, electric is likely to be cheaper and more convenient to use, though not to handle. Air is probably safer - the motor rotor is part of the reason electric angle grinders have a lot of momentum, and it is very important to wait for them to stop before you put them down. I recall some tradesmen who called ten-inch angle grinders "ankle grinders" - you can guess why.

[Bret4207]

Got both. I'd stick with the electric as it's more versatile. Plus, my air grinder freezes my hand after a while.

[RayinNH]

Electric by all means. Much easier to find an electric source than an air source. In your shop it might not matter but if you help a friend out that needs to grind off a rusted bolt the electric will shine in this capacity. The small air die grinders are extremely handy because of their size and you should consider adding one at some point. As Bret mentioned they do get ice cold quickly, especially in the northern climes in winter...Ray

[danski26]

Thanks for the info guys! I picked up a Dewalt 4 1/2" model just now. I was going to go with the Milwaukee brand as I have and like this brand but as suggested by "2400" I looked at the amp's on the plate and the one in stock locally is the 5.5amp model. The dewalt was the only 10amp model they had. $10 less than the Milwaukee also.......Thanks again.

[GLL]

Pneumatic grinders can use a LOT of air ! Make sure your compressor has enough output !

Jerry

[Four Fingers of Death]

Grinders are so cheap nowadays, I have several, one with a cutting disc, one with a grinding disc and one with a special elliptical wood sanding attachment. Saves changing discs mid way through a job. I also have a 9" one that I bought and an air powered one, I haven't used them yet. In fact I have so much stuff, I can't get into my garage to use them :( D'Oh!!

[shooter575]

I have had good luck with the Dewalt.Do get the higher amp model.It comes with better bearings also.

[Blackhawk Convertable]

You are running electricity on both of them, if you think about it. I'd forgo the pneumatic for a grinder myself.

[Bret4207]

My FIL was a body and fender man. Had his own shop from the early 60's till his strokes. He gave me his old ratty 9" B+D STEEL grinder. It was always kinda weak and smelled hot, so last summer I had a local shop go through it and rebuild it. HOLY MOTHER OF PEARL!!!!!!! The first time I tried it I darn near took my leg off!!!!!! I had a 7" hard disc on it and went to grind some weld on a farm implement. It caught right off and I went a@# over tea kettle across the floor! That sucker has some TORQUE!!!

[Mk42gunner]

You definately need to pay attention with the 7" and larger electric grinders, but on a big job they are so much faster than the little ones.

When it comes time to replace the Black and Decker from Walmart; I am going to get one of the Dewalt 110v AC/DC models. That way I can use it in the shop or out in the field from my welder.

Robert

[richbug]

My FIL was a body and fender man. Had his own shop from the early 60's till his strokes. He gave me his old ratty 9" B+D STEEL grinder. It was always kinda weak and smelled hot, so last summer I had a local shop go through it and rebuild it. HOLY MOTHER OF PEARL!!!!!!! The first time I tried it I darn near took my leg off!!!!!! I had a 7" hard disc on it and went to grind some weld on a farm implement. It caught right off and I went a@# over tea kettle across the floor! That sucker has some TORQUE!!!


When there is a real grinding job that needs done I borrow my fathers B&D "Wildcat?" 9" grinder(1984ish vintage). It is a legitimate 15 amp machine, I have blown 15 amp breakers many times when I lean on it too hard. Things can get out of hand fast, if you run 7" wheels on it the torque is unbelievable.

[floodgate]

Even my little "no-name" 5" electric can chase me all around the shop, if I forget and set it down while it is still spinning down. I don't want to even THINK about a 9" version...

Fg

[grumpy one]

I use my 9" Hitachi much more than my small angle grinder, which I only ever use in confined spaces. However you do have to keep your wits about you. When using either stone-cutting or metal-cutting disks, you are cutting with the outside edge and the machine is extremely prone to digging in and jumping wildly forward. Always make sure that will be away from your legs, not toward them. Occasionally the disk shreds when it digs in, hurling pieces of itself radially at extreme speed. That is what the shield is for - always make sure it is between the disk and your head. Of course the noise level is way up into the hearing-damage decibel range, so you need ear protection as well as eye protection. When using face-grinding disks, the hardest thing to get used to is the precession on start-up. Remember that precession occurs at 90* to the axis of acceleration, so the machine twists very vigorously indeed in your hands in a really strange direction, every time you pull the start switch. Start the machine a few feet away from the job, then move it toward the workpiece already running, or you'll wreck the job before you even start on it. I can recall a work-mate refusing to use my Hitachi because of this - he simply declared it to be "uncontrollable". I must admit it would be a lot easier to use if I had three arms and fitted handles on both sides of the gearbox.

[boommer]

I have the millwaukee also the dewalt and have used the Hitachi in 4 inch and I use the mill much more because it,s much more controlable IF I need to really grind down something I will bring out the 9" millwaukee. as for air grinders they are fine if you have a 2 stage compressor and at least 60 gal storage then compressor noise and then your not really mobile you have to be around air. I did dump trailer rebuilds in winter in my shop and I had one air grinder it work great but I HAD THE AIR TO RUN IT CONSTANTLY.

[Four Fingers of Death]

Black and Decker is a pretty ordinary brand nowadays, but there were right up there in quality in the old days. I used a friend's 9" old Makita grinder last weekend, it weighted a ton, but was seriously powerful. I have a lot of good stuff in my shed and some crap. I will gradually convert to DeWalt as I give my business to the Aussies first, allies second. The only aussie company I can think of is Triton, they make wonderful stuff, but centered around woodworking (they are probably made in China, I will have to have a close look). I have had a very good run with Makita in the past, but we're in a shooting war and they're sitting on the sidelines so to speak.

[Russell James]

Had a 4 inch Makita for 20 yrs and just changed a bearing on it!
Still going strong.

[uscra112]

Pneumatic tools can't give you a shock, and they won't make sparks to ignite flammable vapors, but otherwise they have no advantage. I once worked in a building that had been a locomotive facility about 1900. They used a lot of pneumatic tools back then, because portable electric tools hadn't been invented. Heck, there wasn't even an electric grid - the only electricity in that plant they generated themselves, with a steam engine, and it was DC. That's some of the history behind pneumatic tools. They are an anachronism today, IMHO, except for hazardous environments like body shops.

[10-x]

There is a correct tool for every job. No use using a 20 amp electiric grinder with a 7-9 " disk when a 12 amp with a 4" disk will do. Are you working on a tractor or gun part?
One must remember to," Work the Job, don't let the Job Work You".....use the correct tool for the job........its a judgement thing.
Electric grinders are easier to buy and use than air.........most shops have the compressors needed to run air tools..........why spent the $$$ unless you have to. Get a 4" electric and a GOOD Dremel type grinder with 50 or so tools,should be enough.


10-x

NRA Endowment
H.R.M.S.
N.F.A.C.
RVN Veteran

[bearcove]

I'm a welder by trade and have used them all. I've yet to see one that doesn't throw sparks!

[10-x]

Grinding any iron or steel is going to produce "sparks", it's an "unpreventable "event when working with ferrous materials.
I repeat, "Work the job, don't let the Job work You".

10-x


NRA Endowment
H.R.M.S.
N.F.A.C.
RVN Veteran

[Shotgun Luckey]

If you already have the compressor, the air grinder is nice and light, but for serious work, electric might be better

[heathydee]

I always believed the main difference between the two was in the duty cycle. An air powed tool has a 100% duty cycle, because it cools down the longer it is operated. Electic ones get hotter. I have burnt several small electric ones out over the years and now do as 4fingermick does and have one for each type of disc . A 20 dollar 4 inch grinder can give years of sevice in this way.

[leftiye]

IF you were to be doing a lot of fiberglass work, there is an advantage for the pneumatic grinders or sanders. The dust/grindings gets into electric equipmemt and destroys the bearings. Otherwise the electric ones are much handier.

[Dave Berryhill]

Pneumatic grinders can use a LOT of air ! Make sure your compressor has enough output !

Jerry

+1 They are air hogs and unless you have a very large commercial compressor, it will may be running full time to keep up with the air demand.

[Newtire]

If you need torque, go with the electric. If you are looking for a smooth cut, the high speed of an air tool won't allow the burr to grab. If you put too much push into it, it slows down and cuts chunks out.

As far as an angle grinder goes, I would use the electric if I had to slice thru lots of steel unless there was one helluva big air grinder to use.

[Bret4207]

I picked up a 4" cheepy grinder when Woodworkers Warehouse went under for $19.00. I figured it might last through the one job I was doing. That stupid thing just keeps going and going. I haven't been gentle, it sounds like it's loaded with pebbles and it gets hot within 30 seconds, but it just won't die.

Jeeze I miss Woodworkers Warehouse!