I think it's important to realize that these tests are what happens when an undamaged disk is run at a speed greater than its design. Normal failures occur when a disk is damaged during use and flies apart as a result. I would love to see the damages that occur from a normal "within its design speed" test but with damage due to misuse or other. I love seeing how the differing material behave on impacts like this. Great video. You guys put a lot of great thought and planning into your videos. Keep up the great work!
Exactly my thoughts. A normal grinder would never spin fast enough even if your disk did explode on a normal grinder it would not damage near as much as this video shows. 5X less speed therefor force.
There was a really good annotation on the video though, referring to the fact that the biggest issue is people using this big disks on small grinders without a shield. The small grinders spin faster than big grinders, because they're calibrated to have the same velocity at the circumference of the disk, but with a smaller disk. He measured that they tended to explode at around the same RPM that small grinders spin, so the danger is very, very high
I'm sure they could build a rig that pushes steel against the grinding/cutting disk using springs. Just leave it running until the disk wears down enough to fracture.
@@station240 You wouldn't even need to do that, just clamp it in a bench vise too tight, or else clamp it and hit it with a soft mallet a few times, enough to crack, but not enough to bust it in two.
9:37 You can see the part than went through the plywood still had enough energy to bounce off the wall, and in the other camera you can see that it lands next to the other camera at 7:35 This shows how important it is to stand far away, because even though it bounced off a wall it still had a lot of energy.
I think in the 2nd one, he was stuck in a home that was being renovated and had lots of tools. Also, didn't he use a tool chest to chase them down the stairs? (One wonders how he got a 150+ pound chest with hundreds of pounds of tools up to the second floor alone....)
honestly in the two movies they made for that series (the first and Lost in New York) most of his antics would have looked like Saw if the movies were not meant to be family angled with Loony Tunes style injuries. I do not remember where it was posted but a trauma surgeon did once go over Home Alone and the results were pretty much Saw.
When I see things like this, it makes me think of a guy we knew from auto racing in the late 1990s who raced as a privateer against our factory-backed team, and one summer we didn't see him out for several races. When he did come again, he had a particularly nasty scar in his neck and went on to explain that he had suffered a very serious injury working in his shop alone one night, doing something with a grinder that he shouldn't have been doing. He had to drive himself to the hospital while bleeding rather profusely. He was a very nice guy and we were glad to see him back and thankful that he had survived this terrible incident.
Yes! Seems like this normal safety gear does not offer much protection. Would be interesting if those helmets would actually work. I could also think of bullet proof vest, how many layers of paper and - once the lake is frozen, how much ice you need to stop the disk.
Actually I like the idea of testing all sorts of various safety gear in these types of situations just to see how well they help even beyond their rating.
Don Johnson Yeah good idea.. I had a 5 inch disc explode and despite the guard I still ended up with a dozen stitches in my upper leg. Hate to think what it would have been like without the guard.
@@jimmyj2563 I had a nine inch cutting disc kick back, still don't know how it happened but it cut the back of my hand to the bone and severed two tendons, about six months in plaster and physiotherapy to get the use of my hand back and a six inch scar, I was lucky as I have the use of my hand back, and yes the guard was fitted, nine inch grinders are now just for that.
That is actually the situation which shield meant for. Distance between shield and disk is really close, so it shouldn't be dangerous. I mean exploded disk will not be able gain its lethal perspective, shield will absorb most of the disk fragments and even could not get any damage(bending or etc) . So probably fragments will ricochet out of user
on an actual grinder, speaking as the lucky jackass who DIDN'T take the guard off, I got pelted with tiny shrapnel out of the wheel's plane of rotation, but the guard held and was fine. Big bits were redirected away from me (one came almost tragically close to another coworker 20 feet away, but he was missed and was fine after he changed his undies). On this router, the blades are being spun up to 5 times faster than they're designed to, and I'm not sure how you'd go about attaching a guard for testing, but I would surmise the guard would be destroyed (ruined beyond reuse, not shredded) but it would mostly contain and redirect the parts exploding outward. a theoretical user would be safe, but no one else in the area would be.
I'm not a big shop guy but I had to sharpen some drill bits with a wheel at work cuz we were shorthanded. On the last bit, the wheel broke and got me in the mouth. Only took out 3 teeth and chipped 3 others. 60 something stitches in my lip. Turns out maintenance guy had put a wheel in rated for half the rpms that we were running at. Its been a long recovery but definitely feel lucky to be alive. Check your wheels!
I had an experience where I had a 230mm blade disintegrate on a 115mm grinder. No blade guard on it, I had on thick gauntlets and the face shield. When it broke, a decent size chunk hit all four fingers on my left hand. The gauntlet prevented a bad injury from being a crippling injury. My fingers were zig zag.. Do not do stupid shit with grinders. They are not your friend irrespective of how skilled you may be with one. I have enough scars minor and not so minor to prove it. Great informative video!! Much respect from 🇿🇦
Awesome you can try to spin a wire wheel the ones you put on a grinder those are dangerous on a grinder itself pieces of the wire fly off sticking you all the time wonder what it would look like a high-speed they all fly off like little darts of death
Exactly, and put the chronos so we see a top view looking down. The chronos videos in the lab were really cool, one videos looked like blue fire or something like that, I love these videos!
Yeah like you don’t wear sleeves and you have to pull wires out of your arms all day and if you do wear sleeves you run the risk of it getting caught and fucking up your arm
I left a comment elsewhere before I saw this one. I've had a wire brush wheel catastrophically come apart on me before. Had wires stuck all over my arms and torso. Even had 3 wires pin my sack to my thigh
I would like to see some more overpowered kitchen appliances. The "Ridiculously fast way to peel an apple with power tools"-video is still one of my favorites! :) How fast can you make whipped cream? Would a 10 kW toaster be practical? Can you instantly boil an egg?
I know right? When he said to make suggestions for what to do next, the first thing that popped into my head was pretty much exactly what they showed in the teaser.
On Sunday's Twitch stream, discussions about what other items could be launched from that new air cannon barrel. PIZZA was the #1 answer. Like those stereotypical small, cheap, frozen ones. Lauri seemed to really like that idea.😊🍕🍕🍕
Yes, your measurements are quite precise because according to industrial safety standards maximum rotation speed is exactly twice lower than explosion speed. 13600 and 6800.
Oh man this video really was way better, and the first one was pretty good!! I love Anni's cap too -that looks almost exactly like the flame from a flammable liquids warning label that I have! This channel rocks!
Ideas for a future videos from my wife: 1. See what happens when things come in contact with spinning machinery, like simulating hands, ties, etc getting caught in a lathe. You could also compare effects when wearing gloves vs without gloves and see when not wearing them is a better idea. 2. Look at creating explosions using powders like flour, sawdust, or coffee creamer. It's amazing how big those fireballs can get. Keep up the great work! These are always so fun to watch.
the absolute best moment of this is watching that piece of the 2nd disk that tore through the plywood ricochet off the bunker wall at about 9:38 to 9:54
I just ordered the best poly carbonate face shield I could find. Gonna get another for my son. We don't use a 9" grinder but I had a 41/2" disc grenade on me. The guard ate the explosion but it could have been a really bad day. Face shields are cheap compared to plastic surgery and glass eyeballs.
You guys are such a great couple. You can really see you both just love to create this sorta carnagge and have a great time showing it to all us! Keep up the great videos!
Wow, that is an accurate demonstration of how physically dangerous an angle grinder can be without any guard attachments. In the morning I will reattach the guard fitting to my angle grinder. Excellent choice of cameras and their positioning.
This was very impressive I must say. The part of the disc that flew through the plywood and bounced off the concrete wall was amazing and scary. A good reminder that those security precautions that you are taking while making these videos are not too much.
@@midoctor I hope the kinds of people who remove the gaurd and only wear safety glasses with angle grinders will watch this and have a second thoughts. A little bit of convenience or comfort isnt worth the increased risk.
If i calculated correctly, the shrapnel, which hit the blast shield plastic, took 23 frames (0,00644 seconds) from breakage to hit. Calculating from the disc diameter (230 mm) the distance from breaking point to the shield is about 1,2 m. So the shrapnel flew about the speed of 186 m/s, which is 670 km/h or 416 mph. Double-checking 13600 rpm (227/sec) and 0,72 m circumference makes 163 m/s, 587 km/h or 365 mph, which makes sense.
...And if a third of the disc weighs about 200 grams, the momentum in 163 m/s would be 32,6 Ns, which is quite equal to direct rifle shot. en.wikipedia.org/wiki/Newton_second
I absolutely love Lauri and Anni's accents. I must admit that I enjoy them as much as I do all the mayhem. Awesome videos guys. Always look forward to new content 👍🏻
I love how the disks kill only the safety stuff, in order of how horrifying the wounds would be. Eyes, hairline.... Also, I used a grinder at a job once that didn't have the guard. I immediately hit my finger. The guard is clearly needed as evidenced by these really cool videos, and it should only move to rotate to a better place to protect you.
Yeah. I would have expected the safety stuff to do better than it did. It seemed to slice right through without slowing down significantly. I guess I should get a slab of poly-carbonate and make a face shield out of that!
@@ACat1255 I think the problem is that the energy here is too high for any wearable protection. Even if the face shield stops the disk, all that energy gets mechanically transferred to your head and will probably snap your neck.
@@ACat1255 let's be reasonable here. Those wheels are being spun up by a router with a modified chuck Lauri cooked up. in normal use on a grinder they won't get to HALF that speed. Use your guard, use PPE and don't use dodgy wheels.
"That didn't sound good." "That was terrible sound." "Absolutely terrible." "I think it's going to be really bad." But....It was really good. Lesson learned. Don't hide behind the plywood.
A big thank you for this really explicit video of the serious consequences that can cause the use of a sanding disc at a speed higher than that specified or an endomaged disc. This video should serve as an example for metallurgical companies. Really appreciated !
For the 2nd test, the disk was spinning at 210RPS, 12600RPM when it exploded. Edited to add: the diameter of the disk is 230mm, so the edge speed would have been 340MPH (Mach 0.46)
The piece hitting the plywood was impressive!! “Use only according to manufacturers recommendations” seems really important in the case of grinding discs lol.
A very good demo of why you should use a disc at the correct rated speed. This is the sort of test compaies like Norton do in the manufacturing process. They take a wheel at random to the test room for destructive testing i.e. run it up till it explodes under controlled conditions. Cheers guys.
Wish there was a way you could design a device that can harness that energy and launch them at objects or distance somewhat accurately. Awesome video and very educational. Kind of a eye opener for anyone who underestimates the damage a cutting or grinding disc can do.
9:36 look at the part that flies through the wood. It’s moving so fast it goes clean through the wood, bounces off of the concrete, and STILL has enough energy to fly all the way across the screen and out of frame in the other direction just a couple inches off the ground, flying so straight and low it looks like it’s hovering or maybe being suspended by strings. These disks are absolutely no joke.
I would love to see a demonstration of this with the safety guard in place - or since you have put a much larger disc on, if you could fashion a safety shield similar to the one on the grinder - so we can really see what good the safety shield does along with the other safety equipment you should be wearing..
Same idea here. Some of them shake like shit. But hard part will be to spin them fast enough. That small electric motor won't do it. Maybe with gearbox of some kind. And that silage pit is also no go for this. Metal pieces from concrete disk will bounce fly in any direction.
Don't know about the diamond tipped ones but I've seen a composite disc explode from a walk behind saw. My uncle was running it. A piece of the disc nearly the size of my hand shot clean through his calf so fast that he didn't even know it till we informed him that he was bleeding
that would be a wonderful and terrible idea both. First off, those blades are very expensive. Second, they're made of metal, not fused particulate like the grinding disks. That means they weigh almost as much per unit volume, and are less likely to snap. Third, those things are HEAVY compared to even a 9-inch grinding disk, simply because they're over a foot across ('small' ones for masonry saws are 14 inches. if you mean the huge monsters used for street work, those are up to 36 inches) and as such have a lot of material to make them. A home router like Lauri was using won't get those things up to speed without the motor failing--I'd be surprised if it got up to 100rpm. So it's a FUN idea but entirely impractical to try.
Love your videos! I had an experience with a bad collet in a router. The 3/4" (19mm) router bit came out at top rpm and shot out, it went through a 2x12, 2 meters away and was never found again.
I'd have painted some lines, markings and spots on the disc to help with speed estimates and for tracking pieces of the disc when it fragments. Good idea for future exploding disc projects.
Great video showing the danger of grinder wheels.The Occupational Safety and Health Administration here in the U.S says that a grinding wheel blowing up has a 70 to 80 percent chance of killing the person using it, at least with bench grinders,.even with all guards and PPE in place. Biggest mistakes I have seen are people grinding aluminum on wheels designed for steel, using the side of the wheel, and not "ringing" the wheel before mounting, Again, great video, both entertaining and educational..
Thank you for all the work you put into this video. I teach welding and fabrication, I am going to show my students this video to help them better understand the dangers of grinding wheels
Man, the piece that went through the wood bounced off the wall, and continued towards the right of the screen. Amazing video! It's really interesting!!
I've learned 2 things from this video: 1. Face-shields wont do shit if a grinder disc explodes. 2. Exploding grinder discs seem really attracted to helmets. Today was a good day. 😁
Anything spinning at such high RPM has a potential for dangerous situations. A full face shield AND safety glasses are a must. It takes years of being stubborn and dealing with close calls before you realize how important your eyes and face being protected is.
I hope the safety people at SAE,ASTM,UL,etc. are watching and taking 📝 notes on this video. If a worker has one of these"go off"in his or her face,the hard-hat is a joke,that disk makes tossed salad out of your brain and stuffs it in WHATS LEFT of the 👷 hard-hat.
i love you Lauri i love you Anni i love both of your channels, i love your content. i love how humble you two are and i love listening to your accents. *i love you guys*
The thing with the wood vs polycarbonate is that the wood didn't flex and couldn't absorb the impact, where the plastic did deflect and absorb energy, so it didn't allow it to go through.
Hey Lauri, first of all: amazing Vid. That one caught me. The destruction was crazy. Brush Cutters have some crazy attachments. I think about the ones with Chainsaw chains on them. but idk if they are well enough balanced. You could test the Diamond grinder discs. I wouldn't think that they explode, but if, its going to be absolute disaster. Love you both. Thanks!
The levels of destruction unleashed when flywheels & clutches, or when flexplates & torque converters fail in racing applications is insane, and would make for an interesting video.
I know a guy that used the grinder without the guard and chopped off his nose. Doctor managed to reimplant. Crazy is the fact he CONTINUES to grind with 8.5" discs in a 4.5" grinder (obviously no guard as the large disc does not fit).
"Don't try this at home" I wouldn't try anything on this channel at home ! Like I have said before you have the best lives ever, experimenting with all sorts, I envy you so much !!!!! Cheers guys !!!!!
WOW! That second disc test piece that went through the plywood bounced of the concrete wall and went another 20 meters and went under the camera tripod. Another piece went flying behind the camera behind the plexiglass. If you were standing there it would have hit you in the leg!
All jokes aside, this video really really made me rethink my use of power tools. Even tho I understand the maths behind rotational energy, I have been too lazy to use goggles in the past... I think now I'm going to invest in a top quality face mask. I work in prototyping machines, we often use grinders, drills, and die grinders to get the designs to work. As well as at home for my wood working hobby. Drills don't bother me so much, but routers, grinders and circular saws... That's a lot of mass spinning up to and over 10000rpm cheap thin plastics DeWalt glasses are not enough... My router at home goes up to 33600rpm. The cutters are tungsten carbide...
So if you work with a grinding disk, always put a water melon next to you. So if the grinder disk explodes it will go straight for the water melon and you are save.
Putting the Polycarbonate on all 4 sides would give a good demo of it's strength. I use it as guarding on my machines and yes it works well, transparent and strong.
"You can clearly see that the helmet really does something"
-Tell it to the watermelon!
He, it dies with the comfortable feeling that no other watermelon was killed with that piece of shrapnel! xD
It does !!
It catches the disc fragment INSIDE your head !!
@@thetorchchannel357 Exactly what I want to happen in this kind of situation!
Yep it really failed.
The helmet, it does nothing!
I think it's important to realize that these tests are what happens when an undamaged disk is run at a speed greater than its design. Normal failures occur when a disk is damaged during use and flies apart as a result. I would love to see the damages that occur from a normal "within its design speed" test but with damage due to misuse or other. I love seeing how the differing material behave on impacts like this. Great video. You guys put a lot of great thought and planning into your videos. Keep up the great work!
Exactly my thoughts. A normal grinder would never spin fast enough even if your disk did explode on a normal grinder it would not damage near as much as this video shows. 5X less speed therefor force.
@@isaacodegard740 2x speed means 4x energy
There was a really good annotation on the video though, referring to the fact that the biggest issue is people using this big disks on small grinders without a shield. The small grinders spin faster than big grinders, because they're calibrated to have the same velocity at the circumference of the disk, but with a smaller disk. He measured that they tended to explode at around the same RPM that small grinders spin, so the danger is very, very high
I'm sure they could build a rig that pushes steel against the grinding/cutting disk using springs. Just leave it running until the disk wears down enough to fracture.
@@station240 You wouldn't even need to do that, just clamp it in a bench vise too tight, or else clamp it and hit it with a soft mallet a few times, enough to crack, but not enough to bust it in two.
9:37
You can see the part than went through the plywood still had enough energy to bounce off the wall, and in the other camera you can see that it lands next to the other camera at 7:35
This shows how important it is to stand far away, because even though it bounced off a wall it still had a lot of energy.
It flies like that's what it was made for
Sl4yerkid thank god you put this in the comments or someone could’ve gotten hurt
Sl4yerkid i'm pretty sure the part where they attached a grinding wheel to a 30krpm router showed how important it was to stand far away but ok lol.
@@totalcontrol2025 I know you're being sarcastic, but I fail to see what you're trying to say. Obviously my comment has no effect on the past..
Yeah that thing skipped off the ground and just kept on a-going.
If Kevin McCalister had access to his dad's power tools, Home Alone would be over in 2 minutes (and look more like Saw).
There needs to be a R rated remake
I think in the 2nd one, he was stuck in a home that was being renovated and had lots of tools. Also, didn't he use a tool chest to chase them down the stairs? (One wonders how he got a 150+ pound chest with hundreds of pounds of tools up to the second floor alone....)
@@Sky-qd2mf oh but there is a R rated version ruclips.net/video/ZgLqxSPIhR0/видео.html
honestly in the two movies they made for that series (the first and Lost in New York) most of his antics would have looked like Saw if the movies were not meant to be family angled with Loony Tunes style injuries. I do not remember where it was posted but a trauma surgeon did once go over Home Alone and the results were pretty much Saw.
@@filanfyretracker yeah, that's what I mean. You don't need to make Kevin a psychopath, just let the injuries be real.
When I see things like this, it makes me think of a guy we knew from auto racing in the late 1990s who raced as a privateer against our factory-backed team, and one summer we didn't see him out for several races. When he did come again, he had a particularly nasty scar in his neck and went on to explain that he had suffered a very serious injury working in his shop alone one night, doing something with a grinder that he shouldn't have been doing. He had to drive himself to the hospital while bleeding rather profusely. He was a very nice guy and we were glad to see him back and thankful that he had survived this terrible incident.
Need to try this with Military Helmet and Motorcycle Helmet
Yes! Seems like this normal safety gear does not offer much protection. Would be interesting if those helmets would actually work.
I could also think of bullet proof vest, how many layers of paper and - once the lake is frozen, how much ice you need to stop the disk.
@@stoffls ice is strong!
and purple helmet
I should have a British army composite helmet somewhere for Lauri and Anni.
Actually I like the idea of testing all sorts of various safety gear in these types of situations just to see how well they help even beyond their rating.
Your guy's entire channel should be shown at OSHA briefings
I'll be right back guys, gotta go put the guard back on my grinder real quick.
Lmao
Good idea. :D
And never ever remove it again
Don Johnson
Yeah good idea.. I had a 5 inch disc explode and despite the guard I still ended up with a dozen stitches in my upper leg. Hate to think what it would have been like without the guard.
@@jimmyj2563 I had a nine inch cutting disc kick back, still don't know how it happened but it cut the back of my hand to the bone and severed two tendons, about six months in plaster and physiotherapy to get the use of my hand back and a six inch scar, I was lucky as I have the use of my hand back, and yes the guard was fitted, nine inch grinders are now just for that.
Can you guys try with a shield on the grinder and see how well it protects?
It would just fly over the shield...
@Mr T @10x the operating speed it wont be just twisted/distorted, it'll be torn apart. now, hopefully it'll have absorbed some of that lethal energy.
That is actually the situation which shield meant for. Distance between shield and disk is really close, so it shouldn't be dangerous. I mean exploded disk will not be able gain its lethal perspective, shield will absorb most of the disk fragments and even could not get any damage(bending or etc) . So probably fragments will ricochet out of user
on an actual grinder, speaking as the lucky jackass who DIDN'T take the guard off, I got pelted with tiny shrapnel out of the wheel's plane of rotation, but the guard held and was fine. Big bits were redirected away from me (one came almost tragically close to another coworker 20 feet away, but he was missed and was fine after he changed his undies). On this router, the blades are being spun up to 5 times faster than they're designed to, and I'm not sure how you'd go about attaching a guard for testing, but I would surmise the guard would be destroyed (ruined beyond reuse, not shredded) but it would mostly contain and redirect the parts exploding outward. a theoretical user would be safe, but no one else in the area would be.
@@tashkiira7838 my dad got his hand fucked when the grinding wheel exploded
I'm not a big shop guy but I had to sharpen some drill bits with a wheel at work cuz we were shorthanded. On the last bit, the wheel broke and got me in the mouth. Only took out 3 teeth and chipped 3 others. 60 something stitches in my lip. Turns out maintenance guy had put a wheel in rated for half the rpms that we were running at. Its been a long recovery but definitely feel lucky to be alive. Check your wheels!
“The watermelon really didn’t like the grinding disk” lol
It really looks like the other way around. Of two grinding discs, both preferentially targeted a watermelon.
Quickest way to cut a watermelon that I've ever seen. 😀
The grinding disk doesn't like water melons, that's why.
Better hide behind the water bottles 😆 not a single scratch 👍
I had an experience where I had a 230mm blade disintegrate on a 115mm grinder. No blade guard on it, I had on thick gauntlets and the face shield. When it broke, a decent size chunk hit all four fingers on my left hand. The gauntlet prevented a bad injury from being a crippling injury. My fingers were zig zag..
Do not do stupid shit with grinders. They are not your friend irrespective of how skilled you may be with one. I have enough scars minor and not so minor to prove it.
Great informative video!!
Much respect from 🇿🇦
Clearly it's bottles of molten ice. This inevitably happens during summer.
Awesome you can try to spin a wire wheel the ones you put on a grinder those are dangerous on a grinder itself pieces of the wire fly off sticking you all the time wonder what it would look like a high-speed they all fly off like little darts of death
Exactly, and put the chronos so we see a top view looking down. The chronos videos in the lab were really cool, one videos looked like blue fire or something like that, I love these videos!
Yeah like you don’t wear sleeves and you have to pull wires out of your arms all day and if you do wear sleeves you run the risk of it getting caught and fucking up your arm
They stick in eyes particularly nicely, I knew an idiot who thought his reading glasses were adequate PPE
Netyr my father?
I left a comment elsewhere before I saw this one. I've had a wire brush wheel catastrophically come apart on me before. Had wires stuck all over my arms and torso. Even had 3 wires pin my sack to my thigh
I would like to see some more overpowered kitchen appliances. The "Ridiculously fast way to peel an apple with power tools"-video is still one of my favorites! :)
How fast can you make whipped cream?
Would a 10 kW toaster be practical?
Can you instantly boil an egg?
photonic induction!
CIRCULAR SAW CANNON
its like you know exactly what we want :)
I know right? When he said to make suggestions for what to do next, the first thing that popped into my head was pretty much exactly what they showed in the teaser.
On Sunday's Twitch stream, discussions about what other items could be launched from that new air cannon barrel. PIZZA was the #1 answer. Like those stereotypical small, cheap, frozen ones.
Lauri seemed to really like that idea.😊🍕🍕🍕
This is exactly what I wanted👍
"Frozen Ice." ~Lauri 2019
I love how at 9:44 the part of the disk that went through the plywood is coming back
And then goes right under the legs of the camera tripod at the back of the bunker. A near miss for that camera and tripod.
Nice catch. I didn't notice that until you mentioned it.
Yes, your measurements are quite precise because according to industrial safety standards maximum rotation speed is exactly twice lower than explosion speed. 13600 and 6800.
Is that a safety factor of 4.
@@Apjooz that is results in safety factor of 4 since the centrifugal force goes up in square of speed
Beyond the press : Tip for next test, paint a white line on the disc for easier see the rpm in slo mo.
Oh man this video really was way better, and the first one was pretty good!!
I love Anni's cap too -that looks almost exactly like the flame from a flammable liquids warning label that I have!
This channel rocks!
Did you realize that the disc shard that went through the plywood bounced off the concrete and came back? It passes right by the helmet.
Ideas for a future videos from my wife:
1. See what happens when things come in contact with spinning machinery, like simulating hands, ties, etc getting caught in a lathe. You could also compare effects when wearing gloves vs without gloves and see when not wearing them is a better idea.
2. Look at creating explosions using powders like flour, sawdust, or coffee creamer. It's amazing how big those fireballs can get.
Keep up the great work! These are always so fun to watch.
the absolute best moment of this is watching that piece of the 2nd disk that tore through the plywood ricochet off the bunker wall at about 9:38 to 9:54
I just ordered the best poly carbonate face shield I could find. Gonna get another for my son. We don't use a 9" grinder but I had a 41/2" disc grenade on me. The guard ate the explosion but it could have been a really bad day. Face shields are cheap compared to plastic surgery and glass eyeballs.
6:06 I love how the polycarbonate looks like water when the disc hits it!
that is the key to its strength. force absorption
You guys are such a great couple. You can really see you both just love to create this sorta carnagge and have a great time showing it to all us! Keep up the great videos!
How about spinning a carbide tipped saw blade at 30,000 R.P.M.Lauri and Annie??.
Something like a 10" table saw blade!
@@IceBergGeo That would be fun and if it doesn't explode at 30,000 R.P.M.,build a device that will spin it up to 100,000 R.P.M..HAHA!!.
I was going to suggest that too. I feel it would be very mayhem!
And cut through the neighbors house ? Or the one behind it
@@Nz3800 HAHA!!.How about the whole block?.
Wow, that is an accurate demonstration of how physically dangerous an angle grinder can be without any guard attachments.
In the morning I will reattach the guard fitting to my angle grinder. Excellent choice of cameras and their positioning.
I love how much respect you have for your wife ❤️
This was very impressive I must say. The part of the disc that flew through the plywood and bounced off the concrete wall was amazing and scary. A good reminder that those security precautions that you are taking while making these videos are not too much.
Keep doing all these amazing videos, love all the dedication and skill you guys have put into your content.
Excellent safety warning videos. Don't stop this is "preeetty goood" content
@@midoctor I hope the kinds of people who remove the gaurd and only wear safety glasses with angle grinders will watch this and have a second thoughts. A little bit of convenience or comfort isnt worth the increased risk.
If i calculated correctly, the shrapnel, which hit the blast shield plastic, took 23 frames (0,00644 seconds) from breakage to hit. Calculating from the disc diameter (230 mm) the distance from breaking point to the shield is about 1,2 m. So the shrapnel flew about the speed of 186 m/s, which is 670 km/h or 416 mph. Double-checking 13600 rpm (227/sec) and 0,72 m circumference makes 163 m/s, 587 km/h or 365 mph, which makes sense.
...And if a third of the disc weighs about 200 grams, the momentum in 163 m/s would be 32,6 Ns, which is quite equal to direct rifle shot. en.wikipedia.org/wiki/Newton_second
Lauri: I need another three of those cheap grinders.
Clerk: What are you DOING with these things??
I absolutely love Lauri and Anni's accents. I must admit that I enjoy them as much as I do all the mayhem. Awesome videos guys. Always look forward to new content 👍🏻
I love how the disks kill only the safety stuff, in order of how horrifying the wounds would be. Eyes, hairline....
Also, I used a grinder at a job once that didn't have the guard. I immediately hit my finger. The guard is clearly needed as evidenced by these really cool videos, and it should only move to rotate to a better place to protect you.
Yeah. I would have expected the safety stuff to do better than it did. It seemed to slice right through without slowing down significantly. I guess I should get a slab of poly-carbonate and make a face shield out of that!
@@ACat1255 I think the problem is that the energy here is too high for any wearable protection. Even if the face shield stops the disk, all that energy gets mechanically transferred to your head and will probably snap your neck.
@@ACat1255 let's be reasonable here. Those wheels are being spun up by a router with a modified chuck Lauri cooked up. in normal use on a grinder they won't get to HALF that speed. Use your guard, use PPE and don't use dodgy wheels.
@@tashkiira7838 "dodgy wheels"... meaning: don't purchase chinaseum wheels from harbor freight. consider yourself warned.
Nice safety demo video. Will start showing up at safety meetings for industrial workers. Better than first grinder video for sure.
Those discs really, really wanted to kill watermelons that day!
I love these grinding disk videos! Fantastic!
"That didn't sound good."
"That was terrible sound."
"Absolutely terrible."
"I think it's going to be really bad."
But....It was really good. Lesson learned. Don't hide behind the plywood.
you get it as well.Hahahaha! I;m not hiding behind the plywood anymore
A big thank you for this really explicit video of the serious consequences that can cause the use of a sanding disc at a speed higher than that specified or an endomaged disc. This video should serve as an example for metallurgical companies. Really appreciated !
Could you weaken a disk and se what damage it does at right operational speed.
For the 2nd test, the disk was spinning at 210RPS, 12600RPM when it exploded.
Edited to add: the diameter of the disk is 230mm, so the edge speed would have been 340MPH (Mach 0.46)
You have pin point accuracy with your grinder shots. 😁
He's 3 for 3; goggles, facemask and helmet.
Think he's using aimbot?
The piece hitting the plywood was impressive!! “Use only according to manufacturers recommendations” seems really important in the case of grinding discs lol.
"The goggles do nothing!" - Rainier Wolfecastle
Soo friggin funny! “ real acid?” - Rainer wolfcastle
A very good demo of why you should use a disc at the correct rated speed. This is the sort of test compaies like Norton do in the manufacturing process. They take a wheel at random to the test room for destructive testing i.e. run it up till it explodes under controlled conditions. Cheers guys.
I'd love to see a collaboration between these guys and Colin Furze.
Wish there was a way you could design a device that can harness that energy and launch them at objects or distance somewhat accurately. Awesome video and very educational. Kind of a eye opener for anyone who underestimates the damage a cutting or grinding disc can do.
Lession learned: Forget Helmets, get a 2x2m plastic shield.
9:36 look at the part that flies through the wood. It’s moving so fast it goes clean through the wood, bounces off of the concrete, and STILL has enough energy to fly all the way across the screen and out of frame in the other direction just a couple inches off the ground, flying so straight and low it looks like it’s hovering or maybe being suspended by strings. These disks are absolutely no joke.
Standing to the left is still the winning strategy. 3 for 3.
This is one of rare cases where I live the second channel more than the first xD love you guys!
Ice or water, frozen ice
-Lauri, 2019
I would love to see a demonstration of this with the safety guard in place - or since you have put a much larger disc on, if you could fashion a safety shield similar to the one on the grinder - so we can really see what good the safety shield does along with the other safety equipment you should be wearing..
I'd love to see a diamond cutting disc for concrete explode!
Same idea here. Some of them shake like shit. But hard part will be to spin them fast enough. That small electric motor won't do it. Maybe with gearbox of some kind.
And that silage pit is also no go for this. Metal pieces from concrete disk will bounce fly in any direction.
@@soundspark yes they do, my thought exactly.
Don't know about the diamond tipped ones but I've seen a composite disc explode from a walk behind saw. My uncle was running it. A piece of the disc nearly the size of my hand shot clean through his calf so fast that he didn't even know it till we informed him that he was bleeding
that would be a wonderful and terrible idea both. First off, those blades are very expensive. Second, they're made of metal, not fused particulate like the grinding disks. That means they weigh almost as much per unit volume, and are less likely to snap. Third, those things are HEAVY compared to even a 9-inch grinding disk, simply because they're over a foot across ('small' ones for masonry saws are 14 inches. if you mean the huge monsters used for street work, those are up to 36 inches) and as such have a lot of material to make them. A home router like Lauri was using won't get those things up to speed without the motor failing--I'd be surprised if it got up to 100rpm. So it's a FUN idea but entirely impractical to try.
Love your videos! I had an experience with a bad collet in a router. The 3/4" (19mm) router bit came out at top rpm and shot out, it went through a 2x12, 2 meters away and was never found again.
You invented the Amputation Device 5 Million.
Quick and painless :D
Gearloose well... dunno about painless! 🤣
Thank you very much.....now I realize how dangerous grinder
discs are.
4:54 the damagecheese is overwhelming
Passed through the hardhat like nothing. I'm impressed that that sheet of polycarbonate held up!
Explode a disk with a guard on to see how good it is at protecting you and everyone else
I'd have painted some lines, markings and spots on the disc to help with speed estimates and for tracking pieces of the disc when it fragments. Good idea for future exploding disc projects.
This is really all anyone needs to know about effing around whilst grinding.
Great video showing the danger of grinder wheels.The Occupational Safety and Health Administration here in the U.S says that a grinding wheel blowing up has a 70 to 80 percent chance of killing the person using it, at least with bench grinders,.even with all guards and PPE in place. Biggest mistakes I have seen are people grinding aluminum on wheels designed for steel, using the side of the wheel, and not "ringing" the wheel before mounting, Again, great video, both entertaining and educational..
can't believe they didnt mention the piece that flew directly into the tripod
I think you guys have too much fun! Good to watch.
It's worth noting that the fragments appeared to preferentially target "heads".
not really no... if you watch the replays large bits of saw went in all directions
Very educative, your movies actually help me to avoid stupid mistakes at workshop, thank You!
"What is the tables name?"
"Block"
Also, damages/dammit cheese😂
Actually is Lack, but Block could be a better name for it, after this..
@@taurielv it's lack of block :D
@@idvarhurd7804 Yes, just that!
I thought Annie said "Black", ie: IKEA just calls it the colour.
Thank you for all the work you put into this video. I teach welding and fabrication, I am going to show my students this video to help them better understand the dangers of grinding wheels
the polycarb looks like a bubble membrane when impacted
This was fantastic, the work accidents are terrifying!
Not proving anything here, spinning a grinding wheel at twice the rated rpm give four times the force.
Man, the piece that went through the wood bounced off the wall, and continued towards the right of the screen. Amazing video! It's really interesting!!
I've learned 2 things from this video:
1. Face-shields wont do shit if a grinder disc explodes.
2. Exploding grinder discs seem really attracted to helmets.
Today was a good day. 😁
You could always set up a watermelon decoy in the workshop. Any exploding discs should head straight for it🤣
Just like mobile home parks are tornado magnets! :-)
I think that the grinder is the most dangerous handtool that I own. This video was very educational. Thanks.
"Frozen ice" well Lauri. I like my Unfrozen ice :P
Un frozen ice here in R Kansas is known as METH.
y'all still drink unfrozen ice? where i live we drink condensed humidity
Remove it from the freezer to Un-thaw.
So many people say that stupid shit. Even after explaining it they just don't get it.
@@rogermarshall8991 Is that like "hot water heater"....? 🤔🤦🏻♂️🤣
Anything spinning at such high RPM has a potential for dangerous situations. A full face shield AND safety glasses are a must. It takes years of being stubborn and dealing with close calls before you realize how important your eyes and face being protected is.
I hope the safety people at SAE,ASTM,UL,etc. are watching and taking 📝 notes on this video.
If a worker has one of these"go off"in his or her face,the hard-hat is a joke,that disk makes tossed salad out of your brain and stuffs it in WHATS LEFT of the 👷 hard-hat.
i love you Lauri
i love you Anni
i love both of your channels, i love your content.
i love how humble you two are and
i love listening to your accents.
*i love you guys*
I wish the polycarb would have been hit by the big chunk that sailed easily through the plywood. Would it have survived?
No, it would have shattered. Even the first impact tore the bottom loose from the mounting.
The thing with the wood vs polycarbonate is that the wood didn't flex and couldn't absorb the impact, where the plastic did deflect and absorb energy, so it didn't allow it to go through.
Thank you for continuing this. Even if the result was obvious, it is still and important lesson.
The sound of these exploding watermelons is a bit disturbing!
I'm not sure if I like this... lol
Hey Lauri, first of all: amazing Vid. That one caught me. The destruction was crazy. Brush Cutters have some crazy attachments. I think about the ones with Chainsaw chains on them. but idk if they are well enough balanced. You could test the Diamond grinder discs. I wouldn't think that they explode, but if, its going to be absolute disaster. Love you both. Thanks!
Holy shit that thing destroys what ever it touches and doesn't even slow down
More of these please. Nothing better than a lot of random destruction!
42 seconds after upload. Nice!
The levels of destruction unleashed when flywheels & clutches, or when flexplates & torque converters fail in racing applications is insane, and would make for an interesting video.
09corvettezr1 : imagine when the turbine in a jet engine explodes from overspeed...
One piece from second try was flying to the cars, even passed the camera stand. at 7:20
I know a guy that used the grinder without the guard and chopped off his nose. Doctor managed to reimplant.
Crazy is the fact he CONTINUES to grind with 8.5" discs in a 4.5" grinder (obviously no guard as the large disc does not fit).
Only in Finland can you find frozen ice! Lol
"Don't try this at home" I wouldn't try anything on this channel at home ! Like I have said before you have the best lives ever, experimenting with all sorts, I envy you so much !!!!! Cheers guys !!!!!
"polycarponate"
At least they spelled it like they said it
It's made of lots of carp.
Polin Karpo-naatilla on asiaa.
"Rue-in-ed"
Kyy-4
WOW! That second disc test piece that went through the plywood bounced of the concrete wall and went another 20 meters and went under the camera tripod. Another piece went flying behind the camera behind the plexiglass. If you were standing there it would have hit you in the leg!
All jokes aside, this video really really made me rethink my use of power tools.
Even tho I understand the maths behind rotational energy, I have been too lazy to use goggles in the past... I think now I'm going to invest in a top quality face mask. I work in prototyping machines, we often use grinders, drills, and die grinders to get the designs to work. As well as at home for my wood working hobby. Drills don't bother me so much, but routers, grinders and circular saws... That's a lot of mass spinning up to and over 10000rpm cheap thin plastics DeWalt glasses are not enough... My router at home goes up to 33600rpm. The cutters are tungsten carbide...
So if you work with a grinding disk, always put a water melon next to you. So if the grinder disk explodes it will go straight for the water melon and you are save.
As a U.S. Marine , I approve of this video.
Walk away walk away fast
I have to admit I'm drawn towards the horsepower and the destruction!
Putting the Polycarbonate on all 4 sides would give a good demo of it's strength. I use it as guarding on my machines and yes it works well, transparent and strong.
The fact that 2 of these tests / videos, have produced perfect shots, is nothing short of amazing odds.
Nice camera work around 2:40. Plywood/helmet damage scary. All around good job. Thanx.