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Thread: Warning about Routers

  1. #61
    I've never heard of using a router designed for woodwork for grinding.

  2. #62
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    Quote Originally Posted by Jim Becker View Post
    Bill, the big thing with swinging the larger bits with high speeds is the force they generate when they contact the material. So while the cutter might be perfectly fine at the high speed relative to strength and staying together, the effect when/if it grabs a piece of material could have an impact on how many changes of underwear you need to make that day... ...or worse. That's yet another reason why the big cutters must/should be used in a table situation and not with a hand-held router.
    I think most of us realize that Jim,

    My concern was whether a large 3.5” bit would come apart or stay together if my router speed control failed like Mark’s did.

    The answer that the large bits are rated for 25,000 RPM is reassuring. (Looking a different web sites I was unable to find specific speed ratings for the larger bits. Hence the question to the vendor.)

    That was the point I was trying to convey. I was Addressing a safety concern, and in no way suggesting one might want to run large bits at such high speeds...
    Too much to do...Not enough time...life is too short!

  3. #63
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    That's a known thing with older Dewalt ROS's. Mine has done it too.

  4. #64
    --
    I've gone back and forth on this in my mind since reading the original post. Initially I found myself thinking it was an inappropriate application for a woodworking router. After some thought I've come down with the conclusion that a router is simply a motor with a spinning shaft, so what's the problem? Especially seeing as he was using it for very light passes and minimal material removal and (attempting) to stay within the speed ratings of his grinding wheels.

    Either way, the cautionary tale here has not to do with the use of a router for grinding, it has to do with the risks of unreliable speed control.

    Unreliable electronic speed control could create issues in many situations including classic woodworking routing and the OP can be commended for sharing his misfortune to alert others to these risks.

    I've never had this happen myself, but I have taken a Bosch router apart before and noticed the speed control dial mechanism was not particularly robust, even fussy you might say. I wonder if dust, vibration, heat over time might have interfered with it. Or maybe it was a failure in the electronic aspect of the speed control.

    I wonder if the OP will have the router itself examined for the root cause of the failure and report back. I feel really sorry for his injuries.
    Last edited by Jim Becker; 06-11-2019 at 4:35 PM. Reason: Removed quote and response already deleted elsewhere

  5. #65
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    Wow, You are so unfortunate and lucky at the same time. I'm sorry to hear of your accident. I spent my whole career working in machine shops. I've witnessed a few accidents, some that made me cringe. Some types og grinding were always scarier than others. The 30 inch dia blanchard grinder had a magnetic chuck to hold multiple parts. If the power went out, the parts flew. I would never use it during a thunderstorm.
    I also ran a big vertical turrett NC milling machine and found out one day that electronics can and do fail.
    After machining a few parts, the rapid traverse spindle came down and instead of stopping 100 thou above the work, it kept going and buried the cutter in work pc, shattering in the process. I felt something fly through my hair. When all was over, I took off my safety glasses to see that one of the lenses was all ctacked, but didn't completely shatter. That's when I really got shaky, thinking of what might have happened.

  6. #66
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    Sorry you got hurt, but I just don't quite understand what you were trying to accomplish with this setup. Is it deburring? It certainly isn't precision dimensional machining. Can you explain please?

  7. #67
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    Pat, Thanks.

    Hi Pat,


    What I was trying to accomplish with my setup is irrelevant;

    I started the thread to warn people of the potential for sudden failure of speed control, that they may adapt the way they work as necessary to protect themselves from the consequences of such a failure.

    Quote Originally Posted by Pat Barry View Post
    Sorry you got hurt, but I just don't quite understand what you were trying to accomplish with this setup. Is it deburring? It certainly isn't precision dimensional machining. Can you explain please?

  8. #68
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    Quote Originally Posted by Mark Hennebury View Post

    I started the thread to warn people of the potential for sudden failure of speed control, that they may adapt the way they work as necessary to protect themselves from the consequences of such a failure.

    Mark,

    I hope you are recovering well. I read your post with a view to learn, not to judge. Thanks for sharing your experience.

    Regards,

    J.

  9. #69
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    Quote Originally Posted by Mark Hennebury View Post
    What I was trying to accomplish with my setup is irrelevant;

    I started the thread to warn people of the potential for sudden failure of speed control, that they may adapt the way they work as necessary to protect themselves from the consequences of such a failure.
    And good on ya for doing it. Hope you heal quickly.
    Last edited by Lee Schierer; 06-13-2019 at 8:06 AM. Reason: inflammatory language

  10. #70
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    Quote Originally Posted by Mark Hennebury View Post
    Pat, Thanks.

    Hi Pat,


    What I was trying to accomplish with my setup is irrelevant;

    I started the thread to warn people of the potential for sudden failure of speed control, that they may adapt the way they work as necessary to protect themselves from the consequences of such a failure.
    I understand Mark. Surely speed controls can fail and unfortunately you found out the worst way. I'm curious though about two things 1) what speed is/was the lathe running when this happened, and 2) does the router speed control still function properly if the router is running alone, without load?

  11. #71
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    Quote Originally Posted by Anuj Prateek View Post
    kind of related:

    I have a DeWalt and Bosch router.

    DeWalt has switch on the top and I have to extend my fingers to reach it. It always made me a little nervous when switching router on/off - as it compromises the grip on knobs/handle. Now this router stays in router table and I use paddle switch with it.

    Bosch (mr23) has on/off switch on handle. This despite being heavy feels more safe.
    Two things I like about the big PC plunge are the trigger switch along with a master switch, and that the plunge can easily be used while operating with its perfectly placed lever. I have Festool plunges but I just don't like them. As far as spinning a bit they are fine, but they are clumsy. I often work with inside patterns and the PC is just better, get the router in position and pull the switch.

    Mark, I very seldom post on things that went wrong for the very reason you have found. Sad to say.

  12. #72
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    Quote Originally Posted by Mark Hennebury View Post

    I started the thread to warn people of the potential for sudden failure of speed control, that they may adapt the way they work as necessary to protect themselves from the consequences of such a failure.
    Thank you for posting Mark. I have a neighbor that is sometimes an expert witness in court on just these type of electronic failures. Talking to him was eye opening to me (toasters with electronic controls he feels are especially high risk!). I was trusting electronic designs more than I should, and your experience is yet another reminder for me, so thank you for sharing your experience.

    I hope you heal quickly, and fully.

  13. #73
    Mark, I am truly sorry to read about you being injured, but, I am also very sorry to read that you blame everything that happened, on your router and how its speed is controlled. You must admit, that if you had not been doing something that the router is not made for, you probably would not have been injured. It's of no consequence how many times you've done this in the past, it was just an accident waiting to happen. Yes, it was good of you, to inform people about the variable speed adjustment not being trustworthy. But, it was not smart of you, to use the router as you were using it. And you never ever turn your back on any tool that is as dangerous as a router could be, we all know that. So even though I am sorry that you got injured, it's very easy to read between the lines, and realize just how dangerous you were being.

    Len

  14. #74
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    Quote Originally Posted by Mel Fulks View Post
    Mark, just read the whole post... Some of us will now be using full face shields.
    Mine just arrived. Appreciate the heads up from the OP. I own 2 PC 7518 VS routers. Plus a shop full of dangerous tools. No point in pressing my luck any farther.

  15. #75
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    The reason I was asking the questions was to get at the root cause of the problem. Having actually designed and worked with various motor speed controls I thought it would be wise to understand your circumstances better. Not having that, however, I will say that the type of speed control on a router like the one you used is an open loop design. It simply reduces the input voltage supplied to the motor by limiting the peak voltage and / or duration of each of tje 60 Hz voltage cycles. It has no way to monitor the actual speed or do anything to 'control' it. I suspect, in your situation, the rotational speed of the lathe, coupled with the speed of the router itself caused the router to be overcome by the lathe rotational speed. There is no way the router could do anything but "go along for the ride". Effectively the router couldn't keep up and because of the grinding frictional load on the grinding wheel, the wheel ultimately broke. The noise you heard was the wheel fracturing and disintegrating. Again, this wasn't a failure of the router speed control but simply overload due to the conditions that were set up. Maybe this worked for you previously and you were lucky, maybe this time the wheel was degraded enough from previous uses to fail, maybe the load was greater this time, maybe there wad a metal fragment that got into the motor speed adjuster, etc. Who knows.

    Sorry for your injury. Thanks for your initial posting. We can all learn the need for more personal protection when using machines.
    Last edited by Pat Barry; 06-14-2019 at 12:24 PM.

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