Thread: What size grinder?

Hi there,

So you want an angle grinder with real grunt but not a 9 inch (230mm). So that leaves a 4" (100mm), 5" (125) 6" (150mm) and whatever other sizes are available. Not going to get much in the way of quality for $150 but a quick search (using your parameters... real power & not 9") I came up with something like this:
Metabo 1150 Watt Angle Grinder WB 11 150 Quick With A Metabo Disc Brake | eBay

Yea I know. It's $49 over budget but I love Metabo stuff.

Mind you I have a bosch green 100mm angle grinder. I was my first ever real power tool purchase back in 1999 after I was given an arc welder. I hate the feel of Bosch green stuff but it's what I could afford at the time and it's done a lot of work and still going!


Simon

I've got a few makita 4 inch grinders and I am happy with them. My personal preference is for grinders where the safety shield is held to the grinder by screws and not held on by some sort of friction-grippy-band thing (I don't like the idea of the friction grip getting loose and suddenly having a safety shield whizzing around at 9,000 rpm).

My other 'cant' live without' tools are: https://www.alltools.com.au/shop/ind...e_Grinders_%29 and the similar one for a bench grinder.

I have 115 mm , 125mm and a 9inch, all Hitachi.
Wouldn't go any smaller than a 115mm and stay with the better makes like Metabo Makita Hitachi etc. I always ask for the heavy duty tradesman model.

Not sure what you want to do with your angle grinder, but if you are into two handed, heavy duty grinding back of welds then you can't go past a good quality 7" (180mm) grinder. A 9" is really too big for this sort of work but a 7" is ideal. In my opinion a 9" grinder is only for cutting and they do this very well if treated with due respect. They are real beasts that you can't afford to take liberties with.
If you want a grinder for single handed use then a 4" (100mm) is ideal. If you stick to the trade (professional) lines of Makita, Hitachi and Bosch you shouldn't go wrong. I have used all of these and not had any problems. I also still have a 4" Ryobi from the dim dark ages when they did make good gear and it is still in use, primarily for sanding, although it now runs Makita brushes as you can no longer buy the Ryobi brushes for it. I wouldn't touch any of the modern Ryobi stuff!

Cheers,
Alan

Originally Posted by simonl

Hi there,

So you want an angle grinder with real grunt but not a 9 inch (230mm). So that leaves a 4" (100mm), 5" (125) 6" (150mm) and whatever other sizes are available. Not going to get much in the way of quality for $150 but a quick search (using your parameters... real power & not 9") I came up with something like this:
Metabo 1150 Watt Angle Grinder WB 11 150 Quick With A Metabo Disc Brake | eBay

Yea I know. It's $49 over budget but I love Metabo stuff.

Mind you I have a bosch green 100mm angle grinder. I was my first ever real power tool purchase back in 1999 after I was given an arc welder. I hate the feel of Bosch green stuff but it's what I could afford at the time and it's done a lot of work and still going!


Simon

I just happened to look at the Bosch green grinders today while I was killing time in town. The switch was awful. Did not feel reliable and it took me several goes each time to get it to lock. You had to have the pressure just on the right angle. Went back to the Makita just to double check and it was fine. This is a good enough reason not to buy the Bosch.

My opinion is to buy a 125mm with 1100w or more if possible. My Makita is about 800w tho and it is fine. A 100mm grinder has very little wheel diameter to wear. Years ago I did the unthinkable and fitted 125mm wheels to a 100mm grinder with an adaptor ring. I never had any trouble but I would not do it now. The one thing that stood out was that I cut an enormous amount of material before the wheel wore down to 100mm. Several times the work from one disk. 115mm grinders are not as common. Wheels will be harder to find in general.

Do not buy a soft start model unless you intend doing a few long cuts. I use my grinders for a lot of smaller cuts, like most people I would think. I have a 125mm soft start grinder which hardly ever gets used. The slow start up is very annoying after a while.

Re the guards. Watching Keith Fenner videos shows that he does not have guards on any of his grinders that I have seen. He also has an old drill press that has belts going everywhere with not a guard in sight. I cannot do what I do with angle grinders with the guard in place, and you cannot see to cut with them. I will probably get flamed for this. I am not suggesting anyone copy this. You need to make your own decisions on safety. Every new grinder I get I vow to leave the guard on but in a very short time I find I am unable to cut the way I want to.

Not sure what you want to do with your angle grinder, but if you are into two handed, heavy duty grinding back of welds then you can't go past a good quality 7" (180mm) grinder. A 9" is really too big for this sort of work but a 7" is ideal. In my opinion a 9" grinder is only for cutting and they do this very well if treated with due respect. They are real beasts that you can't afford to take liberties with.

This shows how everybody has a different opinion. I would never cut with a 9 inch grinder because if that grinder wheel jams in a cut there is no way anybody can control the power. I have a 7 inch grinder and I only use it for heavy grinding jobs. Its hard to jam a wheel grinding.

Anything bigger than a 125mm is generally too heavy for accurate control. It all depends on the use.

Dean

I would recommend a 5". What i can't recommend is Makita any more. The quality has gone IMHO.

If you want quality buy a German made metabo. VEK tools have some on ebay, i'm not sure if they are German or not though. metabo grinder items - Get great deals on POWER TOOLS items on eBay Stores!

Otherwise i would buy a cheapish one.....When my Makita died last year i was half way through a job. I went to Bunnies and grabbed an AEG. $69? maybe $79, 5", 1100w. Its comfortable, powerful and has no problems with the switch etc. The lead is also the longest i think i have ever had on a power tool. How long will it last? Don't know, since it is made in China by Ryobi......

Dean, i don't know how you use grinders without guards. Although i always use a face shield i hate having to take the guard of a grinder, sparks go in every direction....

Cheers,
Ew

Originally Posted by Ueee

I would recommend a 5". What i can't recommend is Makita any more. The quality has gone IMHO.

If you want quality buy a German made metabo. VEK tools have some on ebay, i'm not sure if they are German or not though. metabo grinder items - Get great deals on POWER TOOLS items on eBay Stores!

Otherwise i would buy a cheapish one.....When my Makita died last year i was half way through a job. I went to Bunnies and grabbed an AEG. $69? maybe $79, 5", 1100w. Its comfortable, powerful and has no problems with the switch etc. The lead is also the longest i think i have ever had on a power tool. How long will it last? Don't know, since it is made in China by Ryobi......

Dean, i don't know how you use grinders without guards. Although i always use a face shield i hate having to take the guard of a grinder, sparks go in every direction....

Cheers,
Ew

I only use safety glasses, and yes the sparks can be annoying, but that welding mask shown in your Avatar picture lets in sparks and sometimes the smell of burning hair and sting of welding blobs is also annoying. I tried wearing a baseball cap under my welding helmet but I have enough problems getting it to sit on properly.

I was cutting some stuff tonight which required that I lean across to see where it was going and I wished that there was a way around the sparks. A guard would stop me from seeing the cut mark. I intend trying a mesh face mask one day. Meanwhile I just keep doing the best I can.

Another issue I see with guards is keeping the grinding disk (I mostly use 1mm disks) straight in the cut so it does not jam and break. It is extremely rare for me to damage a disk to the point it is unusable afterwards. You need a good view to see the whole picture. The worst injury in about 25 years of using an angle grinder is one day the disk touched my knee and ruined a favourite pair of jeans. The skin underneath was scorched. Nothing compared to the jeans.

Dean

I have one of those full clear face shields. The only problem is it does fog up on occasion. Can fit the ear muffs over it too. I use it when using carbide on the mill or lathe. I don't like getting hit anywhere on the face with hot chips......
I had thought anything hot may melt into the clear plastic surface but it seems to be ok so far.

Ew

In my humble opinion 5" grinders are the way to go in as far as power to weight ratios if you get the right power.
Work bought me a new Hitachi G13SB3 - 125mm (5”) Angle Grinder and while I have used a lot of 5" angle grinders, this one is the best of the lot to date .

The Makitas were once the leader of the pack now fall behind due to lack of power and the premature failure of the disc lock button -(I fixed our old one twice)

Also factor in repair as in replacing brushes.Ensure the units brushes can be replaced without a visit to your friendly tool repair shop-you can see the brush cover on the outer case of the grinder.

Be aware that the extra cost of your grinder covers things like better quality and higher power motors. better switches, bearings,replaceable brushes plus a host of other stuff not visible when you pick one up in the store.

I'm a 5" grinder fan, 3 boschs and an 11 year old Ozito that I cannot seem to kill despite repeated use on masonry etc. Blow it out with the compressor and it seems to go on and on . . . . .
The bosch units have full guards on them and the Ozito only has a guard behind the wheel
I cut the front part of the guard off two of the Bosch units otherwise I cannot fit flap wheels onto these.
The Ozito usually has a wire wheel on it, Two of the bosch units have coarse and fine flap wheels, while the 3rd normally is used with a thin kerf cut-off wheel.
I mainly cut stock with a 4" metal cutting bandsaw plus I have an old 8" table saw that I run thin kerf cut-off wheels in - this works very well.
My main problems with grinders have been setting my cotton shirts on fire or melting holes in some poly t-shirts on just under my right tit or armpit but I now have a leather apron which I sometimes remember to put on.

Originally Posted by Ueee

I have one of those full clear face shields. The only problem is it does fog up on occasion. Can fit the ear muffs over it too.

I have 4 sets of Peltor muffs - 2 sets that fit "over the head" and 2 sets "behind the neck muffs" like those shown below which are designed to be used with hats.
The photo shows the muffs have been flipped so they turn into behind the head (instead of behind the neck).
This means the band sits on to of the full face band and holds the full face mask more firmly than it otherwise would.
This is useful for people like me with slightly cone shaped heads especially when there is a lot of leaning over work and the full face mask is likely to slip on a sweaty head.
I use the same setup when chainsaw milling (plus ear plugs as well).

There seems to be a lot of members who like the 5 inch grinders! One thing I don't think has been mentioned is that the 5 inch is the biggest size grinder available in the small form factor.

Another thing with my use of angle grinders. I don't use the tools to tighten the wheels, disks or wire wheels unless a disk (usually cutting) has caught and tightened on. Then I have to search thru the drawer to find the right tool. I believe that tightening further than you can by hand is overtightening and pointless. The direction of rotation tightens the wheel.

The problem I have with face shields is that they fog up very quickly, even in cold weather. This why I am thinking of trying the mesh mask.

Dean

5" definitely seems to be the way to go. 4" seem useless by comparison and 9" grinders scare the willies out of me.

I have the Bosch Blue 5" and it is a really good tool. Cant remember the wattage but it does 11000rpm.
You can lean on it seemingly all day and it just does not care. It has stacks of balls and cuts through stuff in no time with a 1mm blade. I have spent literally hours grinding back welds with it no dramas. It is light and ergonomic enough to cut or grind one-handed no problems.
Note -bosch green is total crap, but the blue stuff seems much better.


For goggles, I use these exclusively now:
Goggle Clear Lens Elastic Band Goggles BY PRO Choice | eBay
NOTHING gets in, nothing. I have had plenty of seriously hot swarf hit them at decent speed and no dramas. (i machine with cermet so my steel swarf comes off blue and melts into your skin)
They are pretty good at anti fog, better than other goggles I've used and the anti scratch is surprisingly good. I get around 6 months out of a pair on the lathe, and it gets used every day. After that they start to get less clear and are relegated off to the grinder, or drop saw etc.


As for face shields, grow a beard ya pack of girls!
Beard use #468 - Protecting from ingress of hot swarf (it really does work)

I have a couple of similar ones made by Uvex. They come with a lower shield that clips on but they are for Girls LOL. I tried using a pair for firewood cutting of "GREEN" wood and with a stiff breeze behind me they still filled up with sawdust. Took them off in disgust and found they have lots of small holes not noticed before. Even where the elastic strap connects with a plastic bracket has holes. I got to work with the silastic and completely sealed them. This worked but I still suffered the same problem I have with all face masks. Fogging up. I tried a normal face mask yesterday for grinding and it fogged up. This is a result of a medical condition. The only recourse is a bucket of water over the head and go hard. Safety glasses also fog up to a degree.

Got to try the mesh mask but I found the normal mask very constricting for movement to see where I am cutting so prob the same.

Re the beard. I wish I could grow one but sensitive skin, probably related to the same problem means that after about a week I feel like tearing my skin off to stop the irritation. The beard would work ok but make it a bit uncomfortable when a bit of welding spatter gets right in and takes a bit to remove. I tend to wait until I have finished a run before I remove offending spatter but sometimes this gets uncomfortable. Couple of weeks ago some got down or thru my sleeve and I thought it would cool down but by the time I finished the run, it was still hot and I had to shake it out from about the elbow. Stung a bit.

Dean

Back in the early eighties I was in Karratha looking to buy a little angle grinder, the come everything kind of store had a huge range of Hitachi power tools on special. Asked the owner why so cheap, informed me Hitachi were going down the gurgler, and he was moving his stock. I went to the bank, came back and bought one of everything he had for sale. Being a m/cycle rider since 1965, i would see that little Hitachi symbol stamped on ignition points regardless of jap m/cycle brand. You could say the rest is history, Hitachi make some big bastard diggers for the mining industry, they bought into Euclid back in 1997 and they are still a going concern. Them tools i bought are all still working, get used when i am home, the most used item is the little quarter inch grinder. I have cut quarter inch steel plate with the jigsaw using a steel cutting blade, before i purchased the gas axe. Hitachi gear has served my needs well


DD