5 ms·

I was using an angle grinder to strip paint off of a large table top and necessarily had to remove the guard. This is one of the most dangerous tools I have and

I was using an angle grinder to strip paint off of a large table top and necessarily had to remove the guard. This is one of the most dangerous tools I have and I'm very aware of it, so I carefully gripped it toward the end of the handle well away from the disk. For the first few minutes I was very conscious about the position of my grip. Then a half hour later I glanced down and saw my top finger about a centimeter away from the spinning disk. I had gradually choked my grip up in order to get better leverage. Another few seconds and it could have become a more memorable incident. I normalized my deviance just by failing to notice it for a few minutes. I see the same forces working on my software practices. For instance I start with wide and thorough testing coverage and over time reduce it to the places I usually see problems and ignore the rest. Sometimes production can be nearly maimed before I notice and adjust my grip.

123yawaworht456 2y ago
> Another few seconds and it could have become a very memorable incident. it takes a bit of pressure for an angle grinder to cut, even when you're cutting soft material like wood. accidental contact with a spinning disc would give you a nasty flesh wound, but you wouldn't lose your fingers or anything. the real danger is the disc breaking up at 10K RPM and shrapnel flying in your face. you might easily lose an eye.
- deleted 2y ago
  [deleted]
- klodolph 2y ago
  That’s not the only real danger. The angle grinder can suddenly shift in practically any direction. It’s very easy to lose control of it.
  - potato3732842 2y ago
    The 4.5" angle grinder is like an agressive little dog that's just waiting for a chance to bite you. The table saw is like an old pitbull that generally sleeps. The 6"/7"/9" grinder is a skunk. Everyone who's ever given it the chance has a story about the time the angle grinder nipped at them. The people who pestered the old pitbull until it got sick of their crap have 9 fingers. Nobody has problems with the skunk because it's pretty obvious what'll happen if you disrespect it.
    - wiredfool 2y ago
      See also: Chainsaws. I used to do a decent amount with them, dropping trees and bucking them for firewood/thinning. Then started doing things like cutting chairs out of bigger logs. I caught myself onetime being really sloppy with where my hands were. All from doing it enough, and then doing something a little more complicated that I probably shouldn't have been doing.
      - lostlogin 2y ago
        There is a saying about aviation and danger that I am probably mangling. The dangerous times are at 100 hours when you think you know that you’re doing, and 1000 hours when you know you know what your doing.
        TeMPOraL 2y ago
        Or back to woodworking, the one saw (!) I always heard was, "When does a carpenter lose a finger? When they stop respecting the saw."
    - ok_dad 2y ago
      Yea, if I have to use my table saw, I’m planning cuts so they perform themselves with guides, and my focus is on pushing the wood properly through the guides while primarily keeping my hands at least a foot away from the blade. My grandfather went through life without his right index finger and it wasn’t too bad for him, but I use a keyboard for a living!
  - convolvatron 2y ago
    thats only a problem if it catches your clothes and gets dragged into your body. only turn the switch into the locked position when really necessary. I usually wear leathers. but if it does happen you're looking at a couple months of road rash, not amputation.
  - agumonkey 2y ago
    And disc blows.
  - TeMPOraL 2y ago
    > The angle grinder can suddenly shift in practically any direction. It’s very easy to lose control of it. Especially when you recoil in pain as it unexpectedly scrapes your finger; it's likely you'll just release your grip entirely, so it'll fly off in a random direction, slicing through anything it hits, possibly bouncing and/or breaking the disk, before it runs out of kinetic energy. $deity help you if the trigger lock is on.
- DavidPeiffer 2y ago
  > the real danger is the disc breaking up at 10K RPM and shrapnel flying in your face. you might easily lose an eye. For anyone wondering, OSHA would tell you to use safety glasses and a face shield. Neither is sufficient protection alone. You should also do the "ring" test before mounting a disc. https://youtu.be/QSQiLxDBpu8 https://youtu.be/QSQiLxDBpu8
  - carlmr 2y ago
    >You should also do the "ring" test before mounting a disc. https://youtu.be/QSQiLxDBpu8 https://youtu.be/QSQiLxDBpu8 Oh, wow that's amazing.
lanstin 2y ago
As you learn in biking, the position and velocities of objects changes smoothly, but awareness of the position and velocities of objects can change very discontinuously.
- digitalsushi 2y ago
  you also learn in biking that a helmet gives you a redo, just like the blade guard does
  - LoganDark 2y ago
    You learn that on basically anything that you can fall or get knocked off of. For me it was an electric scooter!
- mmooss 2y ago
  I've seen that before in reference to flying planes and I assume it's true of driving cars. Do you know the/an authoritative for this topic?
  - lanstin 2y ago
    It's a joke - the real world is generally continuous at the scales of our perceptions, but our perceptions can make errors like not seeing a car off to the side then suddenly becoming aware of it and swerving or screeching to a halt. I think it comes under the rubric of "if you took calculus and then pay attention to your own life."
    - mmooss 2y ago
      It's actually real. IIRC, our eyes and focus move not smoothly, but in discreet jumps. Objects can be overlooked. I think I read that they train professional 'drivers' like pilots how to compensate.
      - lanstin 2y ago
quickthrowman 2y ago
> I was using an angle grinder to strip paint off of a large table top and necessarily had to remove the guard. You did not have to remove that guard, you chose the wrong tool for the job. Chemical stripper and sanding tools exist, use the right tool for the job or next time you might lose that finger.
- Jtsummers 2y ago
  This is also part of the concept of normalization of deviance, though. Selecting tools because of proximity or accessibility rather than suitability. One time you "need" (feeling pressure from somewhere) to get something done and you reach for the tool at hand, it's not the right tool but it's workable. Then later you experience the same thing and think, "Oh yeah, that worked last time I can just do it again." Repeat a few more times and it becomes the tool you reach for instead of your backup when you have nothing else but "need" to get the work done now. Its unsuitability becomes apparent when you injure yourself or cause damage to the items you're working on because it was never the right tool, you were just careful in how you used it the first few times and got too comfortable with it as time went on.
  - bumby 2y ago
    I witnessed this quite a bit in software development. People use the frameworks they are comfortable with, even when they know they can't meet requirements. I've at least had some who were upfront about why by stating "because I don't want to learn something new." (She didn't last much longer)
    - Jtsummers 2y ago
      > "because I don't want to learn something new." I inherited a Visual Fortran program that was written in Visual Fortran because the original developer (who also maintained it for ~15 years) knew Fortran and was not comfortable in other languages. Not because it was a good idea. I was tasked with reimplementing it in C# which was not a bad idea (the target, successful, was to have it as a standalone program or a plugin in another program also written in C#). Almost any language could have been used, but in context C# was a reasonable choice. It's a very common and, to me, very curious attitude. Once you learn how to reason about programs and the logic of programs generally, unless you hit the fringes most languages offer very similar semantics. That said, that particular program was decidedly unstructured (goto's everywhere) so perhaps he really didn't feel comfortable in modern languages or modern uses of his favored Fortran.
PaulHoule 2y ago
Software testing practices are still pretty controversial. I spent about a week redesigning the interfaces of a security-sensitive system to make it testable and developing a test harness, the actual implementation was about a day of work. I felt it was a great use of time. I have not found an answer for testing React components that seems like a good use of resources. I've tried numerous test libraries from Enzyme to react-testing-library and found them all to be terribly flawed (sorry, if you think "I shouldn't have to modify my code to write tests" and then tell me to "use data-testids" that's the end of the conversation. I have an hour to write a test, I don't have two weeks to diagnose how a third party library I use interacts with the Rube Goldberg machine react-testing-library uses to emulate ARIA support) Code that is basically "functional" and doesn't interact with a large mysterious system is straightforward to test; a lot of UI code has the issue that it not only calls a mysterious large and complex system but it also gets called by a mysterious large and complex system. I'd really love to have a system that would give me a heads up that some CSS I changed has a spooky effect on a distance on part of the UI because of the complexity of selectors but that's asking a lot https://understandlegacycode.com/blog/key-points-of-working-effectively-with-legacy-code/ https://understandlegacycode.com/blog/key-points-of-working-... makes the strong test that tests have to be really fast because you should have hundreds or thousands of them that run any build. Feathers makes the best intellectual case for testing when testing is difficult that I've ever seen, but some of the tests I'm proudest of could never run quickly: I built a "Super Hammer" test that ran a race condition prone system with 1000 threads for about 40 seconds that wouldn't have been effective if it was dramatically shorter. You might do 10 builds a day so you could easily do 2500 builds a year and that adds almost 28 hours of waiting a year -- that's just one test but it costs $2800 a year for a fully loaded FTE who costs $100 an hour and probably costs more than that because the long build sets idle hands in motion doing the devil's work and probably wastes several times more time than that.
- pixl97 2y ago
  Companies: "your testing is costing us thousands of dollars" Devs: "So how much does an a few hours of outages cost again?"
  - 2y ago
hinkley 2y ago
If you're not familiar with the shop tool space: A band saw or a table saw can chop off a finger (or three) and surgeons can reattach them. It's very skilled work but you have good odds these days, especially if you've been socialized to put the finger(s) on ice and go to the ER. A hammer press or a grinder, or a few other tools will just take your finger away.
scarecrowbob 2y ago
In my maker space, guards are required. I have taken several trainings with people who use angle grinders professionally and apparently removing a guard is the normal professional practice for a lot of well-founded reasons. This is one reason why I do not want to work in a trade like welding or fabrication professionally. At the same time it indicates that with care it's possible to follow the norms of a profession for long periods of time even if they often seem dangerous. One thing I noticed when I was climbing a lot- the safer and more knowledgeable climbers I went out with used far less redundant equipment (fewer locking or doubled carbiners for instance). At the same time they were far picker about how the equipment was used- one partner would yell at folks to keep hands off the grigri (a belay device that is very common for folks to hold while using). I get why different equipment calls for various "guard rails". At the same time, safety is in the usage and not the devices- forgetting that fact is dangerous in itself.
- rightbyte 2y ago
  > apparently removing a guard is the normal professional practice for a lot of well-founded reasons. Dunno why there are no transparent guard to use when you want to see properly.
  - kps 2y ago
    No good material. The usual material for safety glasses (polycarbonate) scratches easily. A grinder guard would be see-through for about three seconds.
  - scarecrowbob 2y ago
    They kind-of do, but you wear it on your face. FWIW, the reason cited for removing the guards was not vision, but access- it is difficult to get the tool in position when you're working on large objects that can't be re positioned.
    - saintfire 2y ago
      Was going to chime in that this is the reason. I used a grinder almost daily without a guard for years because what i was grinding was 2"+ steel rods buried underground. I couldn't move myself or reposition the work. I'm not advocating removing the guards but there are actual reasons why people hate them. I see some grinders like Milwaukee have guards that can be quickly rotated around the blade. That's not always enough, though. Ive also seen some Welders cut their guards in half, for clearance and at least a shred more safety.
lostlogin 2y ago
I was talking with a friend who runs a building site. One of his crew took the guard off an angle grinder to fit a disc that was designed for a larger tool. With it tucked under his arm he plugged it in. It was already switched on, and when plugged in the cut the artery and nerve to his arm. He survived the blood loss and has most function back but it’s taken a year.
jdietrich 2y ago
For the record, there is a much safer option for this task - a Scotch-Brite disc. The abrasive disc is soft and flexible, so it won't explode into jagged shards or slash through your hand. It'll still give you a nasty nip if you're careless, but injuries are likely to be day-ruining rather than life-changing. https://www.3m.com/3M/en_US/p/d/b5005028018/ https://www.3m.com/3M/en_US/p/d/b5005028018/
- thinkmassive 2y ago
  A flap disc is the more general solution for surface prep and grinding, as opposed to cutting.
  - opwieurposiu 2y ago
    I tried a 3M Cubitron flap disc for the first time last week and it worked great. It really does cut 3x-4x faster than my cheap-o wheels. Soft edges made it easier to blend then my hard grinding wheels.
eternityforest 2y ago
I try my best to treat every violation as a serious incident. The only way I'd take a guard off is if I couldn't afford to get some other tool. I just assume I will fail and forget many steps, and the only thing that might possibly give me a chance of not losing fingers, is following all rules and continually looking for ways to add even more margin.

123yawaworht456 2y ago

> Another few seconds and it could have become a very memorable incident. it takes a bit of pressure for an angle grinder to cut, even when you're cutting soft material like wood. accidental contact with a spinning disc would give you a nasty flesh wound, but you wouldn't lose your fingers or anything. the real danger is the disc breaking up at 10K RPM and shrapnel flying in your face. you might easily lose an eye.

deleted 2y ago
[deleted]
klodolph 2y ago
That’s not the only real danger. The angle grinder can suddenly shift in practically any direction. It’s very easy to lose control of it.
- potato3732842 2y ago
  The 4.5" angle grinder is like an agressive little dog that's just waiting for a chance to bite you. The table saw is like an old pitbull that generally sleeps. The 6"/7"/9" grinder is a skunk. Everyone who's ever given it the chance has a story about the time the angle grinder nipped at them. The people who pestered the old pitbull until it got sick of their crap have 9 fingers. Nobody has problems with the skunk because it's pretty obvious what'll happen if you disrespect it.
  - wiredfool 2y ago
    See also: Chainsaws. I used to do a decent amount with them, dropping trees and bucking them for firewood/thinning. Then started doing things like cutting chairs out of bigger logs. I caught myself onetime being really sloppy with where my hands were. All from doing it enough, and then doing something a little more complicated that I probably shouldn't have been doing.
    - lostlogin 2y ago
      There is a saying about aviation and danger that I am probably mangling. The dangerous times are at 100 hours when you think you know that you’re doing, and 1000 hours when you know you know what your doing.
      - TeMPOraL 2y ago
        Or back to woodworking, the one saw (!) I always heard was, "When does a carpenter lose a finger? When they stop respecting the saw."
  - ok_dad 2y ago
    Yea, if I have to use my table saw, I’m planning cuts so they perform themselves with guides, and my focus is on pushing the wood properly through the guides while primarily keeping my hands at least a foot away from the blade. My grandfather went through life without his right index finger and it wasn’t too bad for him, but I use a keyboard for a living!
- convolvatron 2y ago
  thats only a problem if it catches your clothes and gets dragged into your body. only turn the switch into the locked position when really necessary. I usually wear leathers. but if it does happen you're looking at a couple months of road rash, not amputation.
- agumonkey 2y ago
  And disc blows.
- TeMPOraL 2y ago
  > The angle grinder can suddenly shift in practically any direction. It’s very easy to lose control of it. Especially when you recoil in pain as it unexpectedly scrapes your finger; it's likely you'll just release your grip entirely, so it'll fly off in a random direction, slicing through anything it hits, possibly bouncing and/or breaking the disk, before it runs out of kinetic energy. $deity help you if the trigger lock is on.
DavidPeiffer 2y ago
> the real danger is the disc breaking up at 10K RPM and shrapnel flying in your face. you might easily lose an eye. For anyone wondering, OSHA would tell you to use safety glasses and a face shield. Neither is sufficient protection alone. You should also do the "ring" test before mounting a disc. https://youtu.be/QSQiLxDBpu8 https://youtu.be/QSQiLxDBpu8
- carlmr 2y ago
  >You should also do the "ring" test before mounting a disc. https://youtu.be/QSQiLxDBpu8 https://youtu.be/QSQiLxDBpu8 Oh, wow that's amazing.

lanstin 2y ago

As you learn in biking, the position and velocities of objects changes smoothly, but awareness of the position and velocities of objects can change very discontinuously.

digitalsushi 2y ago
you also learn in biking that a helmet gives you a redo, just like the blade guard does
- LoganDark 2y ago
  You learn that on basically anything that you can fall or get knocked off of. For me it was an electric scooter!
mmooss 2y ago
I've seen that before in reference to flying planes and I assume it's true of driving cars. Do you know the/an authoritative for this topic?
- lanstin 2y ago
  It's a joke - the real world is generally continuous at the scales of our perceptions, but our perceptions can make errors like not seeing a car off to the side then suddenly becoming aware of it and swerving or screeching to a halt. I think it comes under the rubric of "if you took calculus and then pay attention to your own life."
  - mmooss 2y ago
    It's actually real. IIRC, our eyes and focus move not smoothly, but in discreet jumps. Objects can be overlooked. I think I read that they train professional 'drivers' like pilots how to compensate.
    - lanstin 2y ago

quickthrowman 2y ago

> I was using an angle grinder to strip paint off of a large table top and necessarily had to remove the guard. You did not have to remove that guard, you chose the wrong tool for the job. Chemical stripper and sanding tools exist, use the right tool for the job or next time you might lose that finger.

Jtsummers 2y ago
This is also part of the concept of normalization of deviance, though. Selecting tools because of proximity or accessibility rather than suitability. One time you "need" (feeling pressure from somewhere) to get something done and you reach for the tool at hand, it's not the right tool but it's workable. Then later you experience the same thing and think, "Oh yeah, that worked last time I can just do it again." Repeat a few more times and it becomes the tool you reach for instead of your backup when you have nothing else but "need" to get the work done now. Its unsuitability becomes apparent when you injure yourself or cause damage to the items you're working on because it was never the right tool, you were just careful in how you used it the first few times and got too comfortable with it as time went on.
- bumby 2y ago
  I witnessed this quite a bit in software development. People use the frameworks they are comfortable with, even when they know they can't meet requirements. I've at least had some who were upfront about why by stating "because I don't want to learn something new." (She didn't last much longer)
  - Jtsummers 2y ago
    > "because I don't want to learn something new." I inherited a Visual Fortran program that was written in Visual Fortran because the original developer (who also maintained it for ~15 years) knew Fortran and was not comfortable in other languages. Not because it was a good idea. I was tasked with reimplementing it in C# which was not a bad idea (the target, successful, was to have it as a standalone program or a plugin in another program also written in C#). Almost any language could have been used, but in context C# was a reasonable choice. It's a very common and, to me, very curious attitude. Once you learn how to reason about programs and the logic of programs generally, unless you hit the fringes most languages offer very similar semantics. That said, that particular program was decidedly unstructured (goto's everywhere) so perhaps he really didn't feel comfortable in modern languages or modern uses of his favored Fortran.

PaulHoule 2y ago

Software testing practices are still pretty controversial. I spent about a week redesigning the interfaces of a security-sensitive system to make it testable and developing a test harness, the actual implementation was about a day of work. I felt it was a great use of time. I have not found an answer for testing React components that seems like a good use of resources. I've tried numerous test libraries from Enzyme to react-testing-library and found them all to be terribly flawed (sorry, if you think "I shouldn't have to modify my code to write tests" and then tell me to "use data-testids" that's the end of the conversation. I have an hour to write a test, I don't have two weeks to diagnose how a third party library I use interacts with the Rube Goldberg machine react-testing-library uses to emulate ARIA support) Code that is basically "functional" and doesn't interact with a large mysterious system is straightforward to test; a lot of UI code has the issue that it not only calls a mysterious large and complex system but it also gets called by a mysterious large and complex system. I'd really love to have a system that would give me a heads up that some CSS I changed has a spooky effect on a distance on part of the UI because of the complexity of selectors but that's asking a lot https://understandlegacycode.com/blog/key-points-of-working-effectively-with-legacy-code/ https://understandlegacycode.com/blog/key-points-of-working-... makes the strong test that tests have to be really fast because you should have hundreds or thousands of them that run any build. Feathers makes the best intellectual case for testing when testing is difficult that I've ever seen, but some of the tests I'm proudest of could never run quickly: I built a "Super Hammer" test that ran a race condition prone system with 1000 threads for about 40 seconds that wouldn't have been effective if it was dramatically shorter. You might do 10 builds a day so you could easily do 2500 builds a year and that adds almost 28 hours of waiting a year -- that's just one test but it costs $2800 a year for a fully loaded FTE who costs $100 an hour and probably costs more than that because the long build sets idle hands in motion doing the devil's work and probably wastes several times more time than that.

pixl97 2y ago
Companies: "your testing is costing us thousands of dollars" Devs: "So how much does an a few hours of outages cost again?"
- 2y ago

hinkley 2y ago

If you're not familiar with the shop tool space: A band saw or a table saw can chop off a finger (or three) and surgeons can reattach them. It's very skilled work but you have good odds these days, especially if you've been socialized to put the finger(s) on ice and go to the ER. A hammer press or a grinder, or a few other tools will just take your finger away.

scarecrowbob 2y ago

In my maker space, guards are required. I have taken several trainings with people who use angle grinders professionally and apparently removing a guard is the normal professional practice for a lot of well-founded reasons. This is one reason why I do not want to work in a trade like welding or fabrication professionally. At the same time it indicates that with care it's possible to follow the norms of a profession for long periods of time even if they often seem dangerous. One thing I noticed when I was climbing a lot- the safer and more knowledgeable climbers I went out with used far less redundant equipment (fewer locking or doubled carbiners for instance). At the same time they were far picker about how the equipment was used- one partner would yell at folks to keep hands off the grigri (a belay device that is very common for folks to hold while using). I get why different equipment calls for various "guard rails". At the same time, safety is in the usage and not the devices- forgetting that fact is dangerous in itself.

rightbyte 2y ago
> apparently removing a guard is the normal professional practice for a lot of well-founded reasons. Dunno why there are no transparent guard to use when you want to see properly.
- kps 2y ago
  No good material. The usual material for safety glasses (polycarbonate) scratches easily. A grinder guard would be see-through for about three seconds.
- scarecrowbob 2y ago
  They kind-of do, but you wear it on your face. FWIW, the reason cited for removing the guards was not vision, but access- it is difficult to get the tool in position when you're working on large objects that can't be re positioned.
  - saintfire 2y ago
    Was going to chime in that this is the reason. I used a grinder almost daily without a guard for years because what i was grinding was 2"+ steel rods buried underground. I couldn't move myself or reposition the work. I'm not advocating removing the guards but there are actual reasons why people hate them. I see some grinders like Milwaukee have guards that can be quickly rotated around the blade. That's not always enough, though. Ive also seen some Welders cut their guards in half, for clearance and at least a shred more safety.

lostlogin 2y ago

I was talking with a friend who runs a building site. One of his crew took the guard off an angle grinder to fit a disc that was designed for a larger tool. With it tucked under his arm he plugged it in. It was already switched on, and when plugged in the cut the artery and nerve to his arm. He survived the blood loss and has most function back but it’s taken a year.

jdietrich 2y ago

For the record, there is a much safer option for this task - a Scotch-Brite disc. The abrasive disc is soft and flexible, so it won't explode into jagged shards or slash through your hand. It'll still give you a nasty nip if you're careless, but injuries are likely to be day-ruining rather than life-changing. https://www.3m.com/3M/en_US/p/d/b5005028018/ https://www.3m.com/3M/en_US/p/d/b5005028018/

thinkmassive 2y ago
A flap disc is the more general solution for surface prep and grinding, as opposed to cutting.
- opwieurposiu 2y ago
  I tried a 3M Cubitron flap disc for the first time last week and it worked great. It really does cut 3x-4x faster than my cheap-o wheels. Soft edges made it easier to blend then my hard grinding wheels.

eternityforest 2y ago

I try my best to treat every violation as a serious incident. The only way I'd take a guard off is if I couldn't afford to get some other tool. I just assume I will fail and forget many steps, and the only thing that might possibly give me a chance of not losing fingers, is following all rules and continually looking for ways to add even more margin.