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Safety Switch

Discussion in 'SAFETY ISSUES & EQUIPMENT' started by AR. Hillbilly, Apr 11, 2016.

  1. AR. Hillbilly

    AR. Hillbilly United States Active Member Active Member

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    Hi y'all I'm a new guy that just got my first lathe (an old Sheldon) and you have to reach right over the chuck to hit the reversing switch to start the lathe. I have a table saw with a big red flap over the stop button that all you have to do is bump it and it kills the saw. Could I adapt one of these to my lathe in a good location and still keep the reversing switch in the original location? I also wondered about a foot switch? any ideas would be appreciated. I hope I didn't put this in the wrong forum. Thanks in advance. Thad
     
  2. jim18655

    jim18655 United States Active User H-M Supporter-Premium

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    What voltage? Single phase or three phase? What size motor? Are you looking for an emergency stop only or to start/stop?
     
  3. AR. Hillbilly

    AR. Hillbilly United States Active Member Active Member

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    It's a 3/4 hp single phase 120 v or 240 v running on 120 v. I want to kill it if something goes wrong and I'm the only one around. I would like to start and stop it without reaching for the reverse switch. I can release the belt to start and stop the spindle and not reach for the reversing switch with the chuck turning but I'd like a quick kill switch just in case of accident or crash.
     
  4. AR. Hillbilly

    AR. Hillbilly United States Active Member Active Member

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    Can I use a start stop switch inline with the reverse switch?
     
  5. TOOLMASTER

    TOOLMASTER you don't want to know Active Member

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  6. AR. Hillbilly

    AR. Hillbilly United States Active Member Active Member

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    Awesome and thank you.
     
  7. TOOLMASTER

    TOOLMASTER you don't want to know Active Member

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    IF YOU DIG THROUGH THEM SOME HAVE A CASE....I USE THOSE WITH A MAGMET GLUED ON THE BACK SO I CAN MOVE IT WERE IT WORKS BEST
     
  8. jim18655

    jim18655 United States Active User H-M Supporter-Premium

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    There are some foot switches on the same ebay page that you plug in and plug your machine into the switch. You would have to keep your foot on the switch to keep the lathe running.
     
  9. 4gsr

    4gsr Global Moderator Staff Member H-M Supporter-Premium

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    Here's another method of an emergency stop for a machine tool such as a lathe. Is using a pull wire safety switch. Mount it about knee high or just below the chip pan on a lathe. All you have to do is touch it with your leg to activate the limit switch attached to the end of the taught wire and it will trip the relay to the spindle motor. And if you have your machine running on a VFD, you could dynamic brake the motor with tripping the limit switch.

    here's a couple for sale doing an quick search.

    http://www.ebay.com/itm/SIEMENS-3SE...997034?hash=item25b8c967ea:g:n-oAAOSwHgVW8CAF

    http://www.ebay.com/itm/Schmersal-S...f4f940e&pid=100005&rk=3&rkt=6&sd=162013997034
     
  10. uncle harry

    uncle harry United States Active User Active Member

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    The ideal safety switch approach uses a latching contactor to start, stop and/or emergency stop. The contactor has the required number of terminals for the incoming power (single or multi-phase) and an auxillary contact. The auxillary contact (sometimes called a seal contact) latches the contactor by being wired in parallel with a momentary normally open push button. The stop function is done by breaking the flow of current with a normally closed switch. This switch can be a normally closed push button. an E-stop push button, a cable-operated switch (as suggested above) a limit switch or other contact set. Nels (founder of HM) has recently posted a Square D source of wiring symbols & wiring diagrams that covers virtually any motor starting method. That would be a good place to find a diagram for your situation. SAFETY FIRST !
     
  11. British Steel

    British Steel United Kingdom Active User Active Member

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    +1 on the no-volt-release, first it stops the machine coming back to life after a power-out without someone to push the button, second you can usually wire a LATCHING E-stop in series with the coil so it's necessary to both reset the E-stop and push the start button.

    You can wire remote in-series E-stops into circuit too (by the workshop door's good), so your loved ones don't have to dodge your flailing body parts to stop that annoying "whup whup whup" noise distracting them from YouTube as the hamburger circles the spindle...

    Placement: I like the lathe / mill to have a treadle to stomp in an emergency, nice piece of black-and-yellow painted diamond plate with a pair of microswitches in series under it, one each end for reliability, hinged at each end to the lathe cabinet / mill base and a return spring - could be mechanically connected to a brake if your lathe has one / you fitted one?

    A further improvement I did on my lathe, the forward-reverse switch has an extra home-made cam operating a microswitch in it that's in series with the NVR start button and only closes in the "stop" position so I can't power it up without the spindle in "neutral" - it may save me or someone else some time, and as the only people I let use my lathe are people I care about...

    Dave H. (the other one)
     
    uncle harry likes this.

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