Thread: 9" Angle grinders - Safety problems ?

Bob, I would say that the clown who cut through electrical cables would have done the same with a hacksaw.
Not really a fault of the grinder.

Two aspects worry me about grinders and I am the first to plead guilty.

# Using without the guard. Probably doesn''t need explanation, expansion or examples.

# Placing the grinder wheel down, on a surface with the wheel still spinning. You never know where the grinder
might wind up when you do this. I have seen cut electrical cables, cot feet and missing toes as a result of this
practice. Things are even worse when the guard is removed.

Other worries include using the tool in a way that causes the disc to grab, using with a cracked disc and using to cut wood.

Originally Posted by artme

Bob, I would say that the clown who cut through electrical cables would have done the same with a hacksaw.
Not really a fault of the grinder.

I can't remember the exact details but I think he slipped and thats when the grinder went through the cable. I doubt the same thing would have happened with a hacksaw.

. . . . . . and using to cut wood.

, i have not heard that one before.

To cut wood? I am afraid that I am guilty of that when out on a job and there was nothing else to use. They are actually not that bad to cut wood as long as you don't let the disc get too hot and too deep in the cut (it will Jam), but taken steady and a relieved cut, it does the job in a pinch.

I love the irony that someone called "specialist" is the one using an angle grinder to cut wood

Originally Posted by Colin62

I love the irony that someone called "specialist" is the one using an angle grinder to cut wood

It's my guess that anyone will use anything that is at hand to to the job at the time.

Originally Posted by specialist

It's my guess that anyone will use anything that is at hand to to the job at the time.

All grinders have hazards & risks. Very experienced tradesman, even ones with an excellent track record and considered to be very "safe" workers can fall into the trap of "will use anything that is at hand to to the job at the time." I saw the aftermath of what happened to a very good mate with a tangle with a 4" angle grinder with an aluminium cut off wheel (meat axe), just nick off this dag - oops there goes half my hand!

BobL has cited excellent examples from injury research about why grinders are considerd to be so dangerous, but the really dangerous part of a grinder is the operator of the on/off switch.

Generally the power & torque grinders possess is well known, (thats why we use them)
The hazards & risks associated with using grinders not so well known,
Reading of the instructions and safety alerts and actually getting instruction on how to use them safely even less common,

Throwing the instructions / safety warnings away unread (whatever) & ripping into using the tool - everyday occurences.

Using the tool contrary to well documented and well published safety knowledge, and safe operating proceedures - every day occurences - almost universal. Every DIYer and tradie has done it at some time no matter how safety conscious or righteous you are. Used them single handed, guard not fitted correctly, loose workpiece, worn out disk, etc - we have all done it at some point in time. Eventually your luck runs out.

When we consider any one can buy a 4" angle grinder from about $35 upwards and use inferior disks without <st1:stockticker>PPE</st1:stockticker>, or receiving any instruction in its use, or fit very aggressive cutters like Lancelots & Merlins, Arbotechs its a miracle that emergency departments are not packed with grinder injuries.

I know of a fairly recent incident of a woodturner wanting to carve feet on a bowl with a Merlin like cutter in a 4" angle grinder. He was warned not to use it untill a another very well respected woodturner who is very experienced in their use gave him instruction on using it safely. He was also specifically warned by his mate not to use it single handed while hand holding the bowl. No he was too impatient, just wanted to get on with it

Scenario - sitting position, work piece on lap, hand held bowl, single handed grip, very aggressive cutter, no instruction/experience with grinder/cutter combination. Now what could possibly go wrong?

End result a near death experience with a phenomenal number of stitches to the neck almost from ear to ear plus some hand injuries as well.

Originally Posted by artme

Other worries include using the tool in a way that causes the disc to grab, using with a cracked disc and using to cut wood.

In one of his "Bush Mechanic" articles 4WD writer John Rooth was demonstrating how to trim plywood with a 4" angle grinder and this expression:

In another article he said to "throw the durry butt out of the shed window" when there were flammables like paint thinners in use in the shed. In the very next issue someone had written in complaining about Johns somewhat cavalier attitude to safety in his writings and photo's; the magazine printed a reply from Johns wife, whereby the poor man was basically accused of being a safety nazi, a wowser and a typical example of what's wrong with Australia today

Originally Posted by Mobyturns

the really dangerous part of a grinder is the operator of the on/off switch.

When we consider any one can buy a 4" angle grinder from about $35 upwards and use inferior disks without PPE, or receiving any instruction in its use, or fit very aggressive cutters like Lancelots & Merlins, Arbotechs its a miracle that emergency departments are not packed with grinder injuries.

Couldn't agree more. When I used to teach basic mechanical maintenance fundamentals to Navy apprentices one of my biggest headaches was trying to point out that just maybe their Dad's habit of whippersnipping in thongs and maybe a pair of sunnies was not an attitude to emulate, particularly as they move up the food chain towards cutting and grinding tools.

Originally Posted by specialist

It's my guess that anyone will use anything that is at hand to to the job at the time.

Yup. That's the attitude that needs to be beaten out of some people. Along with "Ah, she'll be right".

Originally Posted by specialist
It's my guess that anyone will use anything that is at hand to to the job at the time.



Posted by Chief Tiff
Yup. That's the attitude that needs to be beaten out of some people. Along with "Ah, she'll be right".

While I totally agree with all that has been said in this discussion, there are times that one, ANYONE will use what is at hand to do a job. If you are stuck 30 or 40 k's out of town and doing a job, bearing in mind that I am a Boilermaker, so I am talking about doing a welding job (and woodworking tools aren't normally part of the kit you would take on a field service job) on some sort of machinery and you need a packer, What would you do? Drive back to town for a power saw????, I reckon not. I DON'T ADVOCATE DOING THE WRONG THING, but will as carefully as possible if the need arises.

Have think about other tools, how many of us has used a tool for a purpose that it wasn't designed for, because it was at hand? I would say that 99 out of 100 would have to say they have. What makes a grinder any different?

Something that should be kept in mind is that a disc, either cutting or grinding disc can explode for absolutely no reason, I have seen it happen, you don't have to be doing the wrong thing for it to happen.

As for using those tungsten cutoff discs that they sell for grinders, THEY SHOULD BE BANNED. The only time that I would consider using one of them is on an air grinder which stops immediately the air is shut off. The triggers on them can't be locked on.

As far as I am concerned there is no black and white when dealing these types of tools, yes you use all the protective gear you need, yes you use them as SAFELY as you can, but sometimes you can use them for other things while still staying within those parameters.


Rob

Talking about using the wrong tool for the job the one that really makes my botty squirm is the guy who tried to cut some dacron fishing line by wrapping each end around either hand and then using s table saw
Even if it is a urban myth I know a few eedjets who wouldn't think twice about doing this.

The thought of cutting fishing line on a table saw makes my cheeks clench too!

Nevertheless I vehemently disagree with the assertion that TCT discs be banned. I use all sorts myself: Arbortech Tuffcut for plunge cutting traps in floorboards, Arbortech Pro for carving, and Nicholson and Aussie made circular "hacksaw" blades for sheet metal work and occasional woodcutting.

Never really had a "moment", with any of them that I can recall. I use the regular PPE and 2 hands at all times, and where possible reduce the speed when carving and "Tuffcutting". Two hands and using the grinder's guard as both a pivot and depth of cut limiter aids control immeasurably.

As previously mentioned, I usually only ever use 6", 5" & 4 1/2" grinders for preference as the bigger ones do tend to scare me.

The only time I use the 9" grinder for metal is for cutting deformed bar when setting out for brick & block work. Otherwise the 9" & 12" grinders are for chasing and concrete cutting only.

Nobody has ever shown or even suggested to me how a grinder should be used, so I don"t pretend to be any sort of authority, but I consider a variable speed 5" grinder to be a hell of a lot safer to use than a 9 1/4" saw, for instance. At least in the sort of applications that I use them.

My hatred of steel toothed wheels on grinders is no secret on these forums. I will pose this question in all sincerity."Would you use a circular saw without a retractable guard?" I hope we all answered NO! to that one. How then is an angle grinder with a toothed wheel any different?In a world where, quite rightly, we are expected to leave the workplace in the same condition we arrived, albeit a little more tired, it beggars belief that these flesh munching wheels are still on sale, particularly to the general public. There are so many better and safer ways of doing the job.On another note. Overuse of 1mm cutting discs is possibly one of the bigger hazards I see relating to grinders today. 1mm discs do some things really well and others really poorly. They have no tolerance for side loading, (bad for and cutting disc, but particularly so for the fragile 1mm), are prone to chipping and losing their tension, (going all wobbly), if overheated in the cut. If a wheel was ever likely to fragment, it would be the 1mm. I would also put forward that safety glasses alone are not adequate for grinding/cutting operations, better mono goggles or a face shield.

[QUOTE=Karl Robbers;1755271]My hatred of steel toothed wheels on grinders is no secret on these forums. I will pose this question in all sincerity."Would you use a circular saw without a retractable guard?" I hope we all answered NO! to that one. How then is an angle grinder with a toothed wheel any different?In a world where, quite rightly, we are expected to leave the workplace in the same condition we arrived, albeit a little more tired, it beggars belief that these flesh munching wheels are still on sale, particularly to the general public. There are so many better and safer ways of doing the job.On another note. Overuse of 1mm cutting discs is possibly one of the bigger hazards I see relating to grinders today. 1mm discs do some things really well and others really poorly. They have no tolerance for side loading, (bad for and cutting disc, but particularly so for the fragile 1mm), are prone to chipping and losing their tension, (going all wobbly), if overheated in the cut. If a wheel was ever likely to fragment, it would be the 1mm. I would also put forward that safety glasses alone are not adequate for grinding/cutting operations, better mono goggles or a face shield.[/QUOTE]

"Would you use a circular saw without a retractable guard?" All woodworkers use a table saw at times with out a guard. Personally a hand held circular saw never! Angle grinder with out a guard - never. A "meat axe" not likely to ever find one in my kit.

Whole hearted agree on your points (highlighted) and almost all of your comment. Unfortunately humans see "opportunity" and will get the bright idea to use a tool for a purpose it was never intended nor designed for, because they believe it will make their life easier in that particular circumstance. Thats how humans became so evolutionary significant - by using tools and adapting them!

There are always grey areas and exceptions where a tool or a machine can be used or adapted for another purpose IF the user fully understands the hazards & risks of doing so. Other wise the user may become a contender for a Darwin Award. They often assume a far higher risk in using the tool in the "new" application. Wheter the risk is worth it is up to the individual. The reality is most don't and that is why we fill Emergency Departments on weekends with DIY injuries. I know a fellow wood worker who works in an ortho operating theatre. If you want gory stories just spend some time with him and ask him about hand & leg injuries from power tools. They aren't short of work btw.

My belief is that anyone who uses less than a high impact full face shield plus safety glasses with an angle grinder is quite foolhardy.

Originally Posted by Karl Robbers

Overuse of 1mm cutting discs is possibly one of the bigger hazards I see relating to grinders today. 1mm discs do some things really well and others really poorly. They have no tolerance for side loading, (bad for and cutting disc, but particularly so for the fragile 1mm), are prone to chipping and losing their tension, (going all wobbly), if overheated in the cut. If a wheel was ever likely to fragment, it would be the 1mm. I would also put forward that safety glasses alone are not adequate for grinding/cutting operations, better mono goggles or a face shield.

I agree about safety glasses not being sufficient when using any grinder but I disagree somewhat about 1mm disc being "possibly one of the bigger hazards I see relating to grinders today".
In fact, in terms of grinder control, and if the 1mm discs do break, I think they are one of the safer wheels that can be used.

The fact that they are only available for small grinders and the fact that they are so thin means the angular moment of these wheels is low, so grinder control is easier. When they do make accidental hard contact with material, unlike a thicker more rigid wheel the thin wheels tend to flex and cut, so their kickback forces are smaller. OTOH these things are not to be taken lightly as they will cut flesh deeper and quicker.

I have used several hundreds of these (mainly 125mm) wheels and broken at least a dozen, maybe more.
None have ever completely "fragmented", the majority accidentally exposed to too much sideways force have torn away in one piece at the arbor, spin around the arbor for a second or two, or have fallen onto the bench or the floor. None have flown off like a frisbee. A few have broken various size pieces of them ranging from a few mm through to 20 c sized pieces.

The surface area to weight or volume ratio of the wheel material is such that if pieces do break off they simply do not fly off like a bullet but will tumble and rapidly lose velocity within 10's of cm of their ejection point. I have been hit several time in the hand and in the arm by these pieces and none of these broke any skin. It stings a bit but it's no worse than being hit by a large wood chip coming of a lathe. Unlike when using thicker grinder wheel I don't feel it is essential to always use gloves when using these wheels. Of course just like I would not like to be hit in the eye by a large wood chip coming off a lathe I would not like to be hit in the eye by one of these chips either

Now none of this is an excuse for not wearing PPE and taking all the usual precautions with grinders.
Use two hands to hold the grinder.
Don't use sideways force on wheels designed only to cut
Don't remove the grinder guards
Full wrap around face shield (not just glasses) and muffs are pretty much mandatory.
I generally only use gloves with rigid discs because they tend to make more sparks.
Orient spark generation away from the operator
ETC

Article from the NZ Herald today --

A man has been flown to Wellington Hospital after he walked into a Dannevirke medical centre with an angle grinder embedded in his chest.


The 47-year-old man was using the angle grinder about midday when it kicked back and became embedded in his chest, according to Palmerston North Rescue Helicopter staff.


He was driven to the Dannevirke Medical Centre and he walked in.


Local police and Fire Service staff prepared a street landing site directly in front of the medical centre and the man was flown by the Palmerston North Rescue Helicopter to Wellington Hospital where he was to have surgery.