Angle Grinders Are Dangerous

[AVigil]

While I respect and sympathize for those that have been injured, I have worked with angle grinders in both an industrial setting and at home(which is now my workplace) for almost 3 decades.

I don't quite understand how angle grinders are these "dangerous, don't belong in a knife shop" monsters waiting to burst one of your nads. Use it correctly, wear the gear. I've had many cut-off wheels come apart without injuries. What you need to realize is that these aren't heatguns, dremels or hand drills. They should be treated with as much respect as a 2x72 grinder, drill press, lathe or welding unit. Their size and portability must be what is letting folks put their guard down.

Get a good model with an adjustable "second" grip handle, use the guard(most are adjustable, too) clamp your work down and always be mindful that what you are trying to accomplish is on the agreeable side of physics. I will often run the entire cut in my head before the real thing... and have changed my approach because of potential issues.

But would you feel the same if the cut off wheel came apart and killed you ?

 

[Rick Marchand]

But would you feel the same if the cut off wheel came apart and killed you ?

I would make a point of haunting each and every one you guys. Ricky the Shop Ghost.

 

[kuraki]

I don't understand how this happens. 45 welders on my shop floor, every one of them uses a 4.5" cutoff grinder daily. Often cutting tacked braces and strongbacks off of parts under extreme stress from weld shrinkage, often in odd locations or positions. While I'm sure a disc has come apart once or twice, the most common occurrence of damage seems to be losing a notch off the disc, and at that point it should be tossed, and there are zero injuries in our log due to cutoff discs, vitrified grinding wheels, or flap wheels, coming apart during use.

The only PPE they're required to use while using a cutoff grinder outside of the standard requirements, is a clear safety shield or their welding lid (FWIW any quality self darkening welding lid has a "grind" setting on it's sensitivity adjustment).

If the disc is damaged, throw it away. If it's not running true and balanced, throw it away. If you cannot access the cut in a way that allows you to keep the disc perpendicular to the cut for the entire cut, make two cuts or use a different tool. Cut away from center to prevent the wheel from climbing out of the cut if at all possible. Wear pants, glasses, and a safety shield at minimum. I recommend an apron and gloves on top of that. Position the guard between you and the cut. It's not there to route sparks, it's there to prevent a broken wheel from coming back at you.

 

[Willie71]

30 years of angle grinder use, and one injury. My shirt got caught in a wire wheel, and I ripped a good chunk of skin off my belly. If you feel any vibration in the tool, shut it off and replace the disk. Always cut straight. I won't recommend one to people, because some people can't handle a toothbrush properly, but when used correctly, an angle grinder is a great tool. It has the potential to seriously maim or kill, but so does a drill, lathe, or circular saw. I grew up on a farm, and have had various tools in my hands since I was a toddler. Not everyone has that kind of muscle memory with tools. Know your limitations. Straight cuts, no binding, not too much pressure, and good quality discs are a must.

 

[scott.livesey]

Rule One: Power tools are dangerous. Power tools with rotating blades, saw and grinders, are very dangerous.
Rule Two: Nothing can change rule one. To keep from getting hurt you need to use the tools for their intended purpose and practice using them.
use common sense. don't put your body where sparks or chunks of wheel could hit it. make sure wheel guard is in place and turned to sparks are directed down and away. check your wheels before and after use, if they are chipped or cracked, change them. know the tool's safety precautions and reread them every now and then.
a variable speed 4 1/2" angle grinder is a very useful tool when knife making and should be in every shop along with an assortment of grinding, cutting, and flapper discs.
again, i am glad no one was seriously injured. this thread should remind all of us that knife making tools are dangerous and need to be used with care.
scott

 

[KnuckleDownKnives]

While I respect and sympathize for those that have been injured, I have worked with angle grinders in both an industrial setting and at home(which is now my workplace) for almost 3 decades.

I don't quite understand how angle grinders are these "dangerous, don't belong in a knife shop" monsters waiting to burst one of your nads. Use it correctly, wear the gear. I've had many cut-off wheels come apart without injuries. What you need to realize is that these aren't heatguns, dremels or hand drills. They should be treated with as much respect as a 2x72 grinder, drill press, lathe or welding unit. Their size and portability must be what is letting folks put their guard down.

Get a good model with an adjustable "second" grip handle, use the guard(most are adjustable, too) clamp your work down and always be mindful that what you are trying to accomplish is on the agreeable side of physics. I will often run the entire cut in my head before the real thing... and have changed my approach because of potential issues.

I guess that's why they call them accidents (an unfortunate incident that happens unexpectedly and unintentionally). Unfortunately I can only control how a disk or any attachment is handled after it is in my personal possession. I have ZERO control over how it was handled before it came into my possession. You've been very fortunate to not have had any injuries in 3 decades of use. I've simply pulled one from a package, keyed it up and it has exploded. That's happened to me more than once, and not with a cheap brand where QC may lack. I'm by no means saying they don't belong in a knife shop, and are a monster, but always be aware, be safe.

But would you feel the same if the cut off wheel came apart and killed you ?

I don't recon he would be feeling anything had it killed him. Sh!t happens real quick at 10,000 to 15,000 RPM. A 4" grinder spinning at 10,000 RPM, had a surface speed of over 100 MPH, that calculates to 146 feet per second.

I don't understand how this happens. 45 welders on my shop floor, every one of them uses a 4.5" cutoff grinder daily. Often cutting tacked braces and strongbacks off of parts under extreme stress from weld shrinkage, often in odd locations or positions. While I'm sure a disc has come apart once or twice, the most common occurrence of damage seems to be losing a notch off the disc, and at that point it should be tossed, and there are zero injuries in our log due to cutoff discs, vitrified grinding wheels, or flap wheels, coming apart during use.

The only PPE they're required to use while using a cutoff grinder outside of the standard requirements, is a clear safety shield or their welding lid (FWIW any quality self darkening welding lid has a "grind" setting on it's sensitivity adjustment).

If the disc is damaged, throw it away. If it's not running true and balanced, throw it away. If you cannot access the cut in a way that allows you to keep the disc perpendicular to the cut for the entire cut, make two cuts or use a different tool. Cut away from center to prevent the wheel from climbing out of the cut if at all possible. Wear pants, glasses, and a safety shield at minimum. I recommend an apron and gloves on top of that. Position the guard between you and the cut. It's not there to route sparks, it's there to prevent a broken wheel from coming back at you.

Here is one question that may be an answer to your statement. How does the company or any large shop obtain their grinding/cutting consumables? I bet it's not typically from home depot or lowes where it may be handled by employee that may have dropped it, or a countless number of customers that may have picked it up dropped it and put it back on the shelf. They were probably either dropped of by a vendor rep or mailed in a well packaged box with padding of some sort to protect them from damage to the facility.

I know all of the steel shops I've ever worked at they were either dropped of by a Fastenal rep, CGW rep, Norton rep or other vendor rep and were all probable handled with more care than would be expected from a lowes employee or unacknowledged person walking through one of those stores. You don't see too many hoobyists walking into air gas, grainger or other industrial supplier where typically items like grinding consumables may be behind the counter and can't be handled by the "general public". I'm simply saying I think it may play a large factor into why some of these accidents happen. That and improper use.

 

[Rick Marchand]

pleasenthill....

What you are talking about is how equipment can fail... I get that. There are hidden time-bombs out there in the form of damaged disks and whatnot. I never questioned that aspect of the equation. I have had the same issues on my 2 x 72. I had a brand new belt blow apart upon start up. Thought I had seated it wrong and grabbed a second... bamn... same thing. Loaded up a used one and everything was fine. It was a bad batch of belts that didn't track. That said, I wasn't hurt... because I never stand in front of the grinder on start up... ever!

Regardless of newly keyed up grinders exploding, if you are wearing the gear and walking the walk, it shouldn't be a problem. The worst I've ever had was when a flexible sanding disk caught a sharp corner and kicked the grinder out of my hand, spraining my thumb. It was my fault. I was floating the disk over the surface with an extremely light one-handed grip. Big sweeping motions. I essentially crashed it into a raised perpendicular corner.

 

[Willie71]

I guess that's why they call them accidents (an unfortunate incident that happens unexpectedly and unintentionally). Unfortunately I can only control how a disk or any attachment is handled after it is in my personal possession. I have ZERO control over how it was handled before it came into my possession. You've been very fortunate to not have had any injuries in 3 decades of use. I've simply pulled one from a package, keyed it up and it has exploded. That's happened to me more than once, and not with a cheap brand where QC may lack. I'm by no means saying they don't belong in a knife shop, and are a monster, but always be aware, be safe.



I don't recon he would be feeling anything had it killed him. Sh!t happens real quick at 10,000 to 15,000 RPM. A 4" grinder spinning at 10,000 RPM, had a surface speed of over 100 MPH, that calculates to 146 feet per second.



Here is one question that may be an answer to your statement. How does the company or any large shop obtain their grinding/cutting consumables? I bet it's not typically from home depot or lowes where it may be handled by employee that may have dropped it, or a countless number of customers that may have picked it up dropped it and put it back on the shelf. They were probably either dropped of by a vendor rep or mailed in a well packaged box with padding of some sort to protect them from damage to the facility.

I know all of the steel shops I've ever worked at they were either dropped of by a Fastenal rep, CGW rep, Norton rep or other vendor rep and were all probable handled with more care than would be expected from a lowes employee or unacknowledged person walking through one of those stores. You don't see too many hoobyists walking into air gas, grainger or other industrial supplier where typically items like grinding consumables may be behind the counter and can't be handled by the "general public". I'm simply saying I think it may play a large factor into why some of these accidents happen. That and improper use.

I buy them in boxes of 10 from a local hardware store that carries a lot of industrial tools/supplies. You might have a point there, I've had friends come work in my shop. It's pretty clear when people have experience around tools or not. Stance is very different with an ecperienced tool user from a newbie. How they hold the tool, how they steady themselves, how they position the work are all dramatically different. Some are just not aware of the risk they are putting themselves in. One buddy broke three bandsaw blades on one day. I've broken zero since I bought the bandsaw. I supervised him carefully with the angle grinder, and quickly gave him the hacksaw instead.

 

[Fred.Rowe]

My welding table has 4 right angle grinders set in a rack. I have both big heavy duty 7 inch models as well as 41/2 inch models. The 41/2 inch are used with rotary brushes as well as [6] inch cutting disc. I purchase only the best grade of disc, no WalMart disc. I have a good size metal band saw but there are many cutting jobs that the 6" disc does better. As some have mentioned, "stay out of the line of fire" That spark pattern is there to tell you something, Hot Zone! Even if your not concerned about flying cutting disc, a full face shield with positive air intake keeps the user from ingesting the particles coming off the wheel as it disintegrates as it is used. The bonding agents in the wheels are damned toxic.

In using these little work horses over a 40 year career I have never had one blow a disc apart. Part of that is just dumb luck but much of it has to do with technique and proper gear being worn.

My only reason for posting on this thread is I don't want people to be scared to use these little work horses. I bought and used up a dozen of them over 40 years and I can say they can do many things, save a lot of time and do a huge amount of work and at a reasonable price.

Work safe, Fred

 

[Rick Marchand]

^^^Willie72^^^
Truth

I have friends that are not allowed to use anything outside of files, hacksaws and hand drills. Common sense is uncommon.

True story...

I had a guy attempt to add a serration to his knife by feeding it edge up into the side of a belt... slack portion of a 2 x 72(single speed).

 

[KnuckleDownKnives]

Rick..

I wasn't trying to contradict what you are saying and saying you don't know or really pointing my comment back towards you. Not everyone has 30 years of experience working with these tools. Not everyone has been schooled in their dangers. I've watched people literally pick one up and it scared the hell out of me and I'd want run in the other direction but stopped them immediately. Like "whoa dude you can't use it like that!!!"

I'm trying to word this right. I guess reading that and thinking if I were not experienced and unknowledgeable about them I may take your comment and interrupt it as "they aren't that dangerous and this stuff never happens" but in the wrong unskilled, unknowing hands they can kill, and very fast.

I was simply trying to put it out there in the event that someone who has never picked up a grinder a day in there life happens across this thread and read it and have just a little bit more knowledge of some of the inherit dangers that come with a grinder. The first time I had one explode there weren't forums like these for self learners.

I know personally when I was young and would watch people use power tools that were highly experienced, it looks so easy, i'd think to myself "no problem I can do that, that looks easy". I remember grabbing a skill saw my first time and trying to cut a straight line.. HAHA that joke was on me. Man you could ride a surfboard on that wave.. After 30 years of using one, a skill saw is like and extension of my arm. By simply watching you'd have no idea the death grip I have on it, the muscle memory involved with it, or the large number of things i'm paying attention to as I'm cutting the wood. Like where is the cord at, is it going to catch on the corner and when I get close to it is and bind the saw? When I get to the end of the cut where is the drop going to fall is the saw going to bid if I don't ease the drop off or speed the cut up real fast the last few inches so the drop can't fall before if finish the cut? If something were to happen and I get in a bind what is the saw going to want to do, where and how is it going to want to kick? What they don't see is that just because I'm holding it with one hand and my knowledge of the saw and the power the motor puts out, the grip I have on it is strong enough to stall the 15 amp motor out and not kick much and preventing injury.

To the 16 year old kid who has never used these tools and isn't aware of the dangers I was trying to do list some.

 

[Rick Marchand]

I agree... the intent of my initial response was not to downplay the potential dangers of angle grinders. I just wanted to point out that they are no more dangerous than any other machine that is hellbent on shredding your meat-puppet.

 

[Stacy E. Apelt - Bladesmith]

I will make one comment and then drop back and continue to read.

The problem isn't that angle grinders used with a cut off wheel are dangerous (which many people ignore), ...
or that the angle grinder needs to be of good quality with proper mounting plates and retainers, and use proper thickness and type discs (which many people don't),''''
or that angle grinders are not shaping tools. They are designed to cut straight lines with a cut off disc, or reduce/remove material with a grinding disc (many people use them with a cut off disc to cut out profiles an curves), ...
or that the work needs to be properly clamped down ( many people hold the bar with a foot or hand), ...
or that the people using them need to be trained and wearing the right protective gear and clothing (many don't have any training/experience at all), ...

The problem is that all too often there is a general recommendation of, "Use an angle grinder if you don't want to saw it out".
This recommendation is going to be read by newbies and unskilled people who will buy a plastic HF grinder for $29 and use a $15 ten-pack of HF discs that are pretty unreliable. These people will likely not be aware of any of the above things. A lot of these people will be between 14 and 20. This is a recipe for a serious injury. Maybe it didn't happen to you, maybe it doesn't happen all that often, but sooner or later it will happen to somebody .... and that somebody will likely be an untrained person working in his garage or backyard who read it online. Would you want to read about a serious injury in a thread and know that you were one of those who posted a simple, "Use an angle grinder to cut out blanks."

 

[East Branch Knives]

A big thank you to all the guys that have contributed to this thread. There's a lot of good info on the proper way to use an angle grinder that I'm going to collate into a sheet for my shop. Anyone new to the tool would be wise to read through the posts.

Rick and others, I 100% agree that with proper technique AND safety gear, chances of injury go way, way down. But Pleasanthill's point about the chances of equipment failure increasing w/ bigbox store consumables is well taken; the disc that came apart on me was from HD. And unlike guys that have worked in a shop for years, proper technique can be a difficult thing to master. The comfort and ease using dangerous tools that Willie71, pleasanthill, and others spoke of has been more elusive for me-- my hands are weak and my grip can be unsteady, which is why my welds look like garbage and it takes me weeks to get a knife looking halfway decent. Teaching myself to use these tools has been trying at times because my teacher can be kind of an idiot.

The angle grinder just seems like one of those tools available to a diy-er that has a little extra level of lethality over those like a bandsaw or tablesaw, which may not be apparent to the new user until it's too late. I think the buffer is another.

Thank you again for all the info, guys.

 

[heefageLA]

Whatever you do, for the love of all that is holy, DO NOT GOOGLE 'ANGLE GRINDER INJURY' PICS.

I looked on google to try and find the guy in my area that had his injury and found hundreds of gruesome examples. :barf:

Im absolutely 'gun shy' about using an angle grinder except for easy stuff now...

 

[scott.livesey]

i have seen many posts here and on other forums about using blanks of mild steel and practicing on the belt sander to improve technique. folks need to do the same thing with an angle grinder until they are comfortable using it to grind, sand, and cut. for newbies, check with your local tech school or community college and see if there is a basic metal shop course. my local CC has several that are continuing ed courses, are 30-40 hours long, and some meet only on Saturday. you will save in the long run by having longer tool life and fewer messed up projects.
scott

 

[NC Biker]

I've been using angle grinders for 40 years and have found them to be as safe as any other power tool when used properly and with the manufactures suggested safety gear.

I genuinely don't give a shit if you've done something for x number of years - that in itself isn't proof of anything.

For you Matthew, I offer up the following to back up my claim:

As you can see, while ugly as ever, I still have both my eyes and all 10 fingers.

 

[Bill DeShivs]

Something no one has mentioned: angle grinders produce copious amounts of emery (and other abrasive) dust-much more than a belt grinder.
When those discs wear down so quickly, that dust hangs in the shop air.
Strangely enough, I have never seen people take that seriously.

 

[Rick Marchand]

Something no one has mentioned: angle grinders produce copious amounts of emery (and other abrasive) dust-much more than a belt grinder.
When those discs wear down so quickly, that dust hangs in the shop air.
Strangely enough, I have never seen people take that seriously.

Worth quoting. Angle grinder dust is horrible. I always do mine outside.

 

[Daniel Rohde]

Something no one has mentioned: angle grinders produce copious amounts of emery (and other abrasive) dust-much more than a belt grinder.
When those discs wear down so quickly, that dust hangs in the shop air.
Strangely enough, I have never seen people take that seriously.

This is a VERY good point. The fumes and dust is terrible from angle grinders indoors....