# Forum Home Renovation Tools & Products  Bosch 100mm Angle Grinder - Good?

## curiousbee

Are they good? Saw today that Bunnies have them on a special for $48. Have been wanting to buy an angle grinder for a while. Was thinking of a RYOBI but saw this one today. There was also a special @ Supercheap Auto for Black & Decker 100mm for similar price. any advice? 
Also wanted advice whether to buy 100mm or 125mm. One thought is that as I will not be buying often (as an amateur) and with limited use expect the tool to last, why not buy a 125mm? But I am not sure whether 100mm is more easy to use than 125mm and there can be situations where only a smaller one can be used. Never used one in life but having observed other professionals, feel the need for one. Any advice will be highly appreciated. 
Thanks.

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## shauck

Get 150mm. Can't think of a time I've used it and it was too big, more likely only just big enough (although, that can be from using disc that was worn out and didn't have a spare at the time). I think the bigger they get the stronger you need to control them. Used a demo saw once which had a huge blade and was petrol driven, like a chainsaw body. Man, that required some control. Cut through some pretty thick steel beams. Definitely not a toy which I suppose you know already.

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## r3nov8or

I had a Bosch 100mm angle grinder years ago which cost me around $90. A few years later it stopped.  
I replaced it with two XU1 grinders ($15 each I think). That was a few years ago now, and they are still going. One is for metal cutting and one is for ceramics/masonary. They both fit in the original Bosch carry box  :Smilie:     At todays prices for 'home brands' I should have one for metal grinding too, just so I never have to change a disk until they are worn out - just grab and go...  
For 'non-precision' tasks I struggle to see the value in expensive brands for these small units, unless I was going to use them several times a week. Bigger grinders are a different story due to greater safety concerns, as they add features like soft start, auto-brakes, rotating handles etc.

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## chalkyt

One of the more useful toys in the box. You can cut and grind metal, tiles, concrete etc with the right disc. I bought a 100mm green Bosch after my old Ryobi carked it after many year of hard work. It was on special at the Big Green Shed also. Mind you, I am not sure it is any better than the XU1, Ozito etc units. 
Have used the Bosch a fair bit and so far so good. 100mm has been big enough for any job so far, although for chasing a concrete floor etc a bigger unit is better (how often do you need the depth?). 
Good points with the Bosch are... switch is both momentary push to operate and lock on (the old one was a toggle on and off and occasionally resulted in a chase all over the place if you put it down while still running!), the head can be repositioned so that the switch is on the top or the side, and it has an allen key holder on the cord. 
Bad point is needing to use an allen key to move the guard. Can't always find one if it has fallen out of the holder on the cord since the holder is a bit too flexy. 
Remember that you will get a bit of gyroscopic torque when running, and use your PPE (eyes, hearing, gloves and respirator) as they can be noisy and dusty. (P.S. they can be surgically precise when using very thin blades... you don't even know you have done any damage until you start wondering where the blood is coming from!)

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## curiousbee

Thanks guys. Based on the clue from shauck about more control required for the bigger toy (and a few other threads) I feel that as a novice I should stick to the 100mm for the time being. I dont think I will use it very many times a year and probably this will do. 
On a different note, my temptation has been for a larger toy as recently I tried to take out few stumps from my backyard. they were in an awkward location very close to the retaining wall. Could not dig a lot around them. I had to cut thorough some of the roots to separate them from the stump. I ended up using a circular saw, which needed more space and hence more digging. I felt a angle grinder could have been employed more easily for the job but 100mm would not have been enough to cut through those bl***y thick roots !@# anyway it is done for now. I have a challenge left for one more stump in the front. Will tackle it later.

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## r3nov8or

if you want to cut heaps with one blade, get one of these. comes in various sizes  Multi Cutter TCT 4" Blade - Robson's Tool King Store

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## thebicyclist

> Thanks guys. Based on the clue from shauck about more control required for the bigger toy (and a few other threads) I feel that as a novice I should stick to the 100mm for the time being. I dont think I will use it very many times a year and probably this will do. 
> On a different note, my temptation has been for a larger toy as recently I tried to take out few stumps from my backyard. they were in an awkward location very close to the retaining wall. Could not dig a lot around them. I had to cut thorough some of the roots to separate them from the stump. I ended up using a circular saw, which needed more space and hence more digging. I felt a angle grinder could have been employed more easily for the job but 100mm would not have been enough to cut through those bl***y thick roots !@# anyway it is done for now. I have a challenge left for one more stump in the front. Will tackle it later.

  Please do not cut wood (particularly green roots) with an angle grinder.   
You family finding your disemboweled corpse will not be a good experience. 
One of my uncles has worked as a chippie for 40+ years and has seen more then a dozen people kill them selves very messily and painfuly cutting timber with angle grinders

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## r3nov8or

I have a mate who ended up with a shattered nine inch metal cutting blade in the face. Very lucky to be with us - a strange upper lip but no other ill effects... 
maybe we shouldn't use them at all? 
be careful out there !!!!

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## Pulse

I second the call to not use angle grinders or circular saws on tree roots, seen too many injuries, usually cuts across knees from kickbacks, reciprocating saws work well and you can throw out the buggered blades. 
Cheers pulse

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## shauck

I was taught not to use circular saws on anything round, only square/flat timber. A chainsaw sounds like the right tool to me. Of course not directly in the dirt tho. I never have to pick one up (although I've used them before) as I have a friend who does that for me. He loves cutting down trees. It's his job. Then we have a beer or two after it's all cleared up.

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## curiousbee

mmmmm.... that was strong advice and I guess must be for good reason. The circ saw had been great help in the project, though it heated up and burnt the timber. 
Point noted mates.

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## LordBug

When you get it, just make sure there isn't any run out on the disc. 
I scored a free Bosh 100mm a few years back, and it looks like the bearing is going (The disc very obviously wobbles, so cutting isn't as neat). I'd try to replace the bearing myself, but I can't see any way of removing it easily, so might just jump on a new 100mm grinder. 
I also have strong recommendation for the Ryobi 180mm grinder, I love mine. The 100mm tends to get used for grinding a lot more than cutting, and the 180 does the cutting with more finesse (Larger unit, easier to keep straight I personally find)

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## curiousbee

Having decided that I will buy a 100mm, now the question is the brand. Bosch or RYOBI (unless there are other better deals)? Each of them have two for that size with varying wattage. This link should show all 4 of them at Bunnies: Tools and Hardware - Power Tools - Bunnings Warehouse 
In terms of wattage obviously the RYOBI 950W seems better value, but is that a good way to evaluate these tools?
Any suggestion?

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## stevoh741

my bosch is 7 yrs and copped a flogging. Still works like new. If you want any sort of after sales service (or service at all for that matter) stay away from green shed and use a reputable power tool seller.

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## r3nov8or

> my bosch is 7 yrs and copped a flogging. Still works like new. If you want any sort of after sales service (or service at all for that matter) stay away from green shed and use a reputable power tool seller.

  would agree for a tradie stevoh, but if you can get 3 years domestic replacement warranty on a cheapie, why not?

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## Bloss

:What he said:  Horses for courses - I buy both. I know blokes who have 'perpetual warranty' - a new one every 9-11 months or so replaced under 'warranty'!  :Wink:  
There are plenty of horror stories about tools of all types and angle grinders and chain saws are right up there. I am highly skeptical of the claim in a post above that one person could have seen seen "more then a dozen people kill them selves very messily and painfuly cutting timber with angle grinders" - because although there are many injuries from _all_ tools each year there are actually not all that many deaths and 10-12 from one cause (accepting as given that all those user deaths were while  'cutting timber' is an obvious exaggeration) would show up in ABS and other stats - they don't. 
But when one looks at the OH&S reports power tools are up there, but usually death & injury are from bad handling practices, for example see this graphic report from 2001 http://library-resources.cqu.edu.au/...46/iss_2/JFS4620389.pdf (note it is a French report and incident) - the guy was holding a grinder freehand:_The presence of recent grinding marks 2.30m off the floor and the absence of a ladder led us to suppose that the victim used this device at arm’s length. He probably lost control of the device as the hilt broke (Fig. 6). _ 
He used a 230mm grinder freehand above head height and paid with his life! I am amazed that there aren't more injuries when I see how tools are badly used - I use full face protection with a grinder and ear plugs, I never use a 9"/230mm grinder above waist height and always use two hands. With a chain saw I wear helmet with face guard, ear protection, steel capped boots and loggers chaps Chainsaw Chaps - see why here: Chain saw safety chaps test - YouTube . I have chaps with cuts on them when they did the job they are designed for - experienced operators know their value. I have a friend who understands steel capped boots - he has no toes at all on his left foot and still has the sneaker remains which were cut-off what was left of his foot. 
As to the OP - the 115mm grinders will do most of the work a DIYer would need, they are cheap and wheels are too (so cheap I own several and have them set with different blades - grinding wheel, masonry blade, flap sander, fine cut-off wheel, TCT wood carver and so on, so  can just grab what I need instead of changing the wheel/blade) . Need leather gloves & face and ear protection at minimum IMO. Large grinders only for those jobs where they are the best tool - and treat them with extra caution.

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## TheOtherLeft

> Need leather gloves & face and ear protection at minimum IMO. Large grinders only for those jobs where they are the best tool - and treat them with extra caution.

  I thought it was bad practice to use gloves with rotating machinery, eg grinders, drills etc due to the risk of the glove getting caught and pulling your hand in???

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## manofaus

as already stated when using a portable grinder use gloves, hearing protection and eye glasses as a minium. Get a face sheild as well if you can, leave your glasses on under the sheild. Amazing what will bounce under a face sheild. Also don't use a welding helmet. most lenses are not designed for impact. Make sure you check if you think that you can. Bench grinders (as in fixed) don't wear gloves for items that are smaller then your hand. If you do get drawn into the wheel you will definatly get hurt against the steady or the guard. Use vice grips if you can. Don't grind on the side of the wheel. Don't grind aluminium or brass on any wheel unless it is designed for it.

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## woodchip

> as already stated when using a portable grinder use gloves, hearing protection and eye glasses as a minium. Get a face sheild as well if you can, leave your glasses on under the sheild. Amazing what will bounce under a face sheild. Also don't use a welding helmet. most lenses are not designed for impact. Make sure you check if you think that you can. Bench grinders (as in fixed) don't wear gloves for items that are smaller then your hand. If you do get drawn into the wheel you will definatly get hurt against the steady or the guard. Use vice grips if you can. Don't grind on the side of the wheel. Don't grind aluminium or brass on any wheel unless it is designed for it.

  Really good advice that, (as are the other posts above). 
The angle grinder is definitely the most dangerous tool in my kit, eye injuries, hand injuries, etc.
Often get tempted to use the 100mm grinder with one hand & hold the item being ground in the other hand, but stop myself just in time!! very bad practice!! 
I have a Makita 100mm grinder for yrs & has been good, but often find it too small for some cutting tasks, with the Ryobi/Bosch options on curiousbee's last post....I would buy the blue Bosch 125mm & have a fantastic grinder that will last a lifetime & feel(& enjoy) the trade quality of it everytime I picked it up. 
cheers

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## Bloss

> I thought it was bad practice to use gloves with rotating machinery, eg grinders, drills etc due to the risk of the glove getting caught and pulling your hand in???

  This is OK - but this was about angle grinders, and a hand held angle grinder is not 'rotating machinery' in this sense: the wheel certainly rotates, but you should never be feeding anything by hand towards or near the rotating wheel. I would argue a drill isn't either, (I am not after a semantic debate here . . . ) but a drill doesn't throw waste material (in the case of metal red hot) away from it at high speed in normal use and operation - an angle grinder does. But for a grinding wheel on a bench grinder, saws and so on gloves are not generally worn, but when to use safety gear is always a risk based assessment - hard for DIYers who might be oblivious to the risks (of wearing and not wearing for example).

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## Handyjack

I have a 100mm angle grinder. It is a Ryobi and I bought it in October 1989. It sees the occasional use. There are times when I wished I had a bigger size such as when cutting paver's. The blade, apart from wearing down fast, did not allow me to cut half way through from both sides.
The other thing to consider is that there is only one dealer for repairs and spare parts for Ryobi, other makes may have more options. With that said at under $100 I would consider taking a risk with any tool. Depending on use it could be many years before it needs any repairs by which time you will have forgotten the purchase price. 
I wear gloves when using an angle grinder due to hot waste flying off the wheel. I also keep a pair of safety googles in the box with the grinder so I always have a pair to wear.

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## curiousbee

[QUOTE=Handyjack;868825]There are times when I wished I had a bigger size such as when cutting paver's. The blade, apart from wearing down fast, did not allow me to cut half way through from both sides. 
What kind of pavers are you referring to? Keen to understand that as I plan to lay some pavers soon and may need to cut them too.

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## shauck

On the blades wearing down quickly, It is important to not force the tool through the material you are cutting and also the more steady and straight you hold it, all the way through the cut, especially as you get deeper into the cut, you will get longer life from your disc. As example, I've been able to cut through a good 20 sheets of tin before needing to change disc (150mm grinder). It's a tool that requires a lot of attention.

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## Handyjack

[QUOTE=curiousbee;868986]  

> There are times when I wished I had a bigger size such as when cutting paver's. The blade, apart from wearing down fast, did not allow me to cut half way through from both sides. 
> What kind of pavers are you referring to? Keen to understand that as I plan to lay some pavers soon and may need to cut them too.

  The paver's are 190x390x40. What I do remember is that I was using a stone cutting disc, I might have done two paver's (cutting on both sides) before changing disc. If I was to do the job again I would use a diamond blade. I managed to cut one paver using a wet saw (neighbour had tradie laying paver's). In August 2010 I bought a 230mm angle grinder (also Ryobi) with a diamond blade. Cuts through bricks like a knife in butter - just dusty and noisy. The machine has a soft start  :Smilie:  and you can turn the handle 90 degrees left or right from the head.  :2thumbsup:  An auxiliary handle is provided and can be fitted in three positions. Only thing is it is moderately heavy and did not have a case. I have since made a box for it but need to remove disc to store in said box. I can keep various discs in the box and additional spindle discs. 
Angle grinders can be hired with diamond blades. 
Hope this helps.

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## r3nov8or

If you are going to cut a lot of pavers hire a wet table saw with a diamond blade. These are made specifically for the job. Wet cutting equals no dust. Usually a daily fee plus a charge 'per micron' of the blade used.

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## stevoh741

or like my last hire tell them you are only cutting 2 pavers and pay no extra charge......despite cutting about 50!

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## r3nov8or

they'd be silly not to measure the blade.  
some people are silly  :Smilie:

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## Tannwin

> they'd be silly not to measure the blade.  
> some people are silly

  They are usually hired with a diamond tipped blade

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## r3nov8or

> They are usually hired with a diamond tipped blade

  Yep, and diamond blades wear down, which is why they are (sometimes) measured and the wear charged for separately.

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## chalkyt

Hi Curiousbee 
This might be a bit late for you, but I was at the local plumbing supply place today and noticed that they are having a "new year clearout". On the bargain table was a Metabo 125 Angle Grinder for $220 incl GST. I think that these are usually around $300+, so even with freight it seems like a good buy. I don't need one, otherwise it would be MINE now. I have had a Metabo drill for over 30 years, it has renovated three places and still going strong (just looks a bit ugly like the rest of us). If of interest, call Jindabyne Plumbing Supplies 02 6456 1842

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## shauck

I realised yesterday that my angle grinder is 125mm, not 150mm.  :Doh: So anything I said earlier about getting bigger angle grinder, I would have to say 125mm has been doing it very well.

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