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Bad day at work

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  • Bad day at work


    This morning we had an accident at my job. I'd set one of the guys to grinding some pins on the center grinder. I went back to my bench to start some building, when after about an hour I heard a sharp snap and shrapnel hitting the walls.

    The wheel had exploded and either a work piece hit him in the chest and head, or a piece of the wheel. He was blacked out for a little better than a minute.

    We got to the ER, and he should be fine, but just a reminder to all of us, be safe in what we do!!!! Some things we do as machinists can get you very badly hurt if you don't follow the rules.

    If you think you understand what is going on, you haven't been paying attention.

  • #2
    Any idea why the wheel blew? Are the wheels you use spin tested 100%?
    Free software for calculating bolt circles and similar: Click Here


    • #3
      Hell, It doesn't matter if you do follow all the rules, If it is going to getcha it will.
      Play it safe anyway.


      • #4
        Got to tell a similar true story from my history to "the new guy" at work today. My story had a fatal ending though.

        This guy started working with us this week, and even though he's 40 he kind of bounces around like the UPS guy on Mad TV. I took a few minutes while training him to polish shafts with emery cloth on the lathe that even a seemingly benign operation like this needs just as much attention as anything else. Trying to rush so as to accomplish more is OK at a track meet, but is downright shameful when standing in front of a 21" lathe.

        I hope he was paying attention, but it's hard to tell since it's like pulling teeth trying to complete a sentence without ricocheting on a tangent with this guy.

        I'll keep trying. Fortunately it's up to me whether and when he operates any of the machine tools.


        • #5

          I mount all the wheels myself and spin all new mountings for 1/2 hour before for doing any work.

          The parts he was grinding don't allow getting the wheel off the part. They are really nasty to make. Normally I would do these myself, for fear of just such an accident as happened. But today things were stacked up.

          From what I got out of him in the ambulance, (I'm also an EMT in town), on the trip in, he must have "jammed" the wheel into the part.

          I hear you IOWolf, some days you get the bear, some days the bear gets you. Still, I feel bad. I perhaps over judged his abilities to do the job.

          If you think you understand what is going on, you haven't been paying attention.


          • #6
            New wheels from reputable manuacturers are spin tested to 150% of rated rpm. I wouldn't count on that with some of the imports.
            Free software for calculating bolt circles and similar: Click Here


            • #7
              sorry to hear that and glad it wasn't worse. my shivers-down-the-spine fear in the shop is a grinding wheel letting go
              in Toronto Ontario - where are you?


              • #8
                Things can sneak up on you. I was runing a CNC lathe one day and the cabide boring bare broke, a piece of it shattered the safety glass on the lathe. Scared the **** out of me. No injury only the safety glass damaged messy to clean up all those little pieces of tempered glass. Have heard a lot of war stories fortunaly have seen few ,and experenced even less by the grace of God. A speedy recovery to the co worker.
                When I worked in the grinding shop there was a guy that worked like his shirt tail was on fire . He scared the older experienced guys. Some of the parts we worked on were worth tens of thousands and the tolerances were in tenths. Not an enviroment where you should rush the work.
                Ad maiorem dei gloriam - Ad vitam paramus


                • #9
                  Dowels generally are small, this sounds kinda unusual unless the dowel caught between the housing and wheel?, i never had a wheel blow but i use the side of them quite often even though its a no-no, I wont hold heavy material up to a wheels side and am careful in front --- to me this is what could really blow a wheel is having a heavy peice of material "clunking" the hell out of your grinding wheel, oh yea, stand to the side whenever possible...
                  Last edited by A.K. Boomer; 03-15-2007, 08:55 PM.


                  • #10
                    I always run my cutting and grinding wheels up for the first time and let them spin for while. Can't say I do it for every use though. I do check my grinding wheels for chipped edges. I guess I better start now. Glad your co-worker will be ok.

                    I wonder if it was put on too tight or it crashed into something prior to his use?


                    • #11
                      Your supposed to keep your body out of the line of fire so if it does blow your not in the direct path.

                      I had a wheel shatter on a toolpost grinder once,I was clear of it,but one half went in the chip pan and the other went through the roof.
                      I just need one more tool,just one!


                      • #12
                        At my first job we ordered grinding wheels by the case. Brand new case of wheels, all ring tested good, but after the third one exploded we sent the shipment back. No one was hurt, but the overhead lighting was in sorry shape.



                        • #13
                          I used a good sized crankshaft grinder many years ago at school. That big old wheel was very impressive and quite ominous as it spun almost silently in it's housing. I always cringed a little when bumping the edge of a crank throw to grind the radius.
                          THAT OLD GANG 'O MINE


                          • #14
                            Wheels are one area I don't save a buck, especially on the 9" angle-grinder.
                            All name brand.
                            Just got my head together
                            now my body's falling apart


                            • #15
                              The grinding wheel is the one tool I own that scares me the most. With everything else I can normally see the danger like a key in a chuck or such. With the stone you are at the complete mercy of the integrity of the stone. Was it dropped or handled rough in shipment and how would you know if it was?

                              I have some pink wheels that I use for sharpening the HSS stuff but never really get to develop any serious pressure on them but they are 60 grit which always makes me wonder how strong they can be at that grit?

                              Maybe it was a cheap lesson for your worker and he still gets to go home at the end of the day. Probably got the rest of the crew thinking better about what they're doing.
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