Exploding cutting disc

  • Thread starter wolram
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  • #1
wolram
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Now we know Evo is ok ish i will tell of my latest,

While cutting a seized inner bearing off a 60 mm shaft the cutting disc exploded and cut my finger to the bone, luckily i was wearing a a safety mask as a shard cut a grove in it, the last time i used a cutting disc i set my overalls on fire.
 

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  • #2
Moonbear
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Oweeeeee!!!! What part of your finger? Are you going to lose function of it, or was it someplace that you can recover?

Okay, that's it, I'm making a new PF rule...NO MORE INJURIES!!!! :grumpy:
 
  • #3
wolram
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Oweeeeee!!!! What part of your finger? Are you going to lose function of it, or was it someplace that you can recover?

Okay, that's it, I'm making a new PF rule...NO MORE INJURIES!!!! :grumpy:

A nice diagonal cut along the top of my pointing finger from nail to knuckle, washing it out hurt more than the cut its self, it wont bend very much but i heal up quick.
 
  • #4
turbo
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Woolie, do you have gloves? Cutting disks on rotary tools are pretty notorious for disintegrating and angular momentum distributes the shards pretty efficiently.
 
  • #5
Astronuc
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When using a cutting disk, I used to wear impact resistant safety googles or visor, leather glooves - and a welders vest or apron - depending on location. Don't take chances.
 
  • #6
wolram
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Woolie, do you have gloves? Cutting disks on rotary tools are pretty notorious for disintegrating and angular momentum distributes the shards pretty efficiently.
I intend to put some gloves on order, as for an apron Astro some of these bearings are are in such awkward places an apron is more a hindrance than a help.

I guess a cutting disc some times kicks back like a chain saw, not that i have ever used one,
it would be interesting to know why the disc acts so.
 
  • #7
lisab
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Ouch - getting fingers cut is painful - sorry to hear about that, Woolie :frown: . Sounds like it could have been worse, and good thing you were wearing your sheild. How much time off work will you miss?
 
  • #8
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Small ones have broken on me. They seem to break after a slice in the metal has been cut making the groove, and the discs break if I happen to move the spinning disc a little putting it out of alignment with the groove. The pressure on the sides of the disc gets the disc caught and can't turn--then breaks.
 
  • #9
wolram
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Ouch - getting fingers cut is painful - sorry to hear about that, Woolie :frown: . Sounds like it could have been worse, and good thing you were wearing your sheild. How much time off work will you miss?
It aint all that bad lisab, and i wont miss any work, if i had not worn the face mask i might have been missing my nose, now that would have made me miss work.
 
  • #10
Moonbear
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A nice diagonal cut along the top of my pointing finger from nail to knuckle, washing it out hurt more than the cut its self, it wont bend very much but i heal up quick.
I always hate that first immersion of the cut under water...I know it's going to sting and it's so hard to make myself do that.

On the up side here, the back of your finger where you cut it is the unbendy side, not the bendy side (that's really technical anatomical terminology for you :biggrin:), so if the biggest trouble you're having is bending your finger, you're probably okay.
 
  • #11
Evo
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Good Grief, we need to get you a kevlar suit too!!! We've got to keep you safe so that you break the "Funniest Member Guru" curse. :surprised
 
  • #12
wolram
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Good Grief, we need to get you a kevlar suit too!!! We've got to keep you safe so that you break the "Funniest Member Guru" curse. :surprised
I guess i wont be all that funny if i am not covered in jelly or on fire or spouting blood, heck i am afraid to go to work now.
 
  • #13
~christina~
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well it could be worse...

I was reading a true crime novel the other day and they were investigating a case where a woman had been stabbed and there was blood all over the kitchen her body was found. After reconstructing the crime scene and the events leading to her death, they found that she had inadvertently killed herself. They found that she had tried to wash a chicken whist cutting it under a running faucet. She had drank a few glasses of alcohol and then had cut her finger to the bone whist cutting this chicken. The blood spattered all over the counter and she tried to reach for bandaids. :rolleyes: Whist doing this, she cut her wrist with the same knife. (blood is all over the kitchen now) Then, trying to get help after the 2 cuts, she slipped on her own blood and the knife became embedded in her chest, thus killing her.
Yes, it could be worse.

Hope it heals fast, Wolram :smile:
 
  • #14
Integral
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I always manage to leave a bit of blood on a wrench type job. I figure that if you don't donate a bit of blood, you are not serious about it. Wolie, you must be one serious dude! :cool:
 
  • #15
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Glad you had some protective gear on!
 
  • #16
AhmedEzz
glad to hear its not a serious injury. Always remember -wolram & the rest of PF :rofl:- " Safety first! "
 
  • #17
wolram
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well it could be worse...

I was reading a true crime novel the other day and they were investigating a case where a woman had been stabbed and there was blood all over the kitchen her body was found. After reconstructing the crime scene and the events leading to her death, they found that she had inadvertently killed herself. They found that she had tried to wash a chicken whist cutting it under a running faucet. She had drank a few glasses of alcohol and then had cut her finger to the bone whist cutting this chicken. The blood spattered all over the counter and she tried to reach for bandaids. :rolleyes: Whist doing this, she cut her wrist with the same knife. (blood is all over the kitchen now) Then, trying to get help after the 2 cuts, she slipped on her own blood and the knife became embedded in her chest, thus killing her.
Yes, it could be worse.
:rofl::rofl::rofl:
 
  • #18
Moonbear
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well it could be worse...

I was reading a true crime novel the other day and they were investigating a case where a woman had been stabbed and there was blood all over the kitchen her body was found. After reconstructing the crime scene and the events leading to her death, they found that she had inadvertently killed herself. They found that she had tried to wash a chicken whist cutting it under a running faucet. She had drank a few glasses of alcohol and then had cut her finger to the bone whist cutting this chicken. The blood spattered all over the counter and she tried to reach for bandaids. :rolleyes: Whist doing this, she cut her wrist with the same knife. (blood is all over the kitchen now) Then, trying to get help after the 2 cuts, she slipped on her own blood and the knife became embedded in her chest, thus killing her.
Yes, it could be worse.

Hope it heals fast, Wolram :smile:
:bugeye: Don't give anyone any new ideas on how to injure themselves! :surprised
 
  • #19
Redbelly98
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Now we know Evo is ok ish i will tell of my latest,

While cutting a seized inner bearing off a 60 mm shaft the cutting disc exploded and cut my finger to the bone, luckily i was wearing a a safety mask as a shard cut a grove in it, the last time i used a cutting disc i set my overalls on fire.
Wow, what size disk (diameter, thickness) and on what type of tool (power drill, Dremel rotary tool, circular saw, other?)

If you can, go to a disk that is either thicker, or of smaller diameter. OR go to a lower-rpm tool (eg. if you're using a rotary tool, try a drill instead)

Abrasive disks are notoriously brittle. Especially those thin 1-inch (25 mm) disks used on fast-spinning rotary tools, they break most easily. I can imagine two main modes of failure:
1. the disk is partway through the cut, and gets twisted "out of plane" while at high speed and in the confines of the cut slot. Snap!
2. a small notch develops somehow in the outer edge, which then catches on the edge of the cut slot. Snap!
 
  • #20
devil-fire
Just be sure to cut straight and the chances of the disks exploding are almost zero unless of course your cutting something that will contract when being cut, pinching the blade. If for some reason you can't cut straight (cutting on an awkward angle or whatever), then keep the cut wide so there is some room between the disc and material being cut, or use a thicker disc.

Usually I just use safety glasses, gloves, coveralls and try to position my head on one side of the disc or the other, so if it comes apart, my face isn't in the way. Coveralls do a good job at protecting from pieces flying off, but they burn through fairly quickly so try to aim the sparks away from yourself or at least stand back some
 
  • #21
wolram
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This my good friend, or one like him, i cut two groves at an angle so they meet just above
the shaft, then whack it with a big hammer and chisel, this leaves a half inch so intact as i can not cut right up to the part the bearing butts up against.

http://www.screwfix.com/prods/91103/Power-Tools/Grinders/Site-230mm-Grinder-240V;jses [Broken]
 
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  • #22
Redbelly98
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Okay, looks like a reasonably thick disk. Are slightly smaller diameters available that are still compatible with your tool? Or can you run at a slower speed than you have been?

Some more thoughts on cutting technique:

As your cutting a slot through the wall of a hollow shaft ***, there are two ends to the slot. At one end, the disk will tend to skip out of the slot; at the other end, the disk tends to dig deeper into the slot. Enlarge the slot by cutting at the end the disk wants to skip out of.

To reiterate one of devil-fire's hints, try cutting the slot to be wider than the disk. I.e., as if you are really cutting two slots that overlap each other. Then it's less critical to keep the disk in the exact same plane as the slot.

Regards,

Mark

*** p.s. is your shaft solid or hollow? (I mean the one with the seized bearing, of course ... :biggrin:)
 
  • #23
Borek
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I always manage to leave a bit of blood on a wrench type job. I figure that if you don't donate a bit of blood, you are not serious about it.
If you are serious it is always blood, tears and sweat.

These disks are like grenades. I have seen effects of a small one exploding. Luckily nobody was hurt (close to a miracle) but shards went so deep into brick wall they were hard to remove.
 
  • #24
wolram
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*** p.s. is your shaft solid or hollow? (I mean the one with the seized bearing, of course ... :biggrin:)
Solid hollow shafts??? the one with the bearing is a 60mm s/steel solid joby, the discs i use start of quite big but theres not much of them when i am done.
 
  • #25
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I love my dremels and the reinforced cutting wheels.
 

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