ML7 reversing switch

  1. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    My Myford is getting a little bit of a tart up, NVR for a start. It’s always had this little reversing switch, not the type I’ve seen on other machines but I’ve never questioned it as it works. But I wouldn’t mind replacing it with something metal clad, if such a thing is available. Any ideas where I can get one?

    925EF6E8-B66C-45DA-AD28-AA586FEA902C.jpeg 937547A4-A54F-451E-9653-6E0AD4E75188.jpeg
     
  2. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
    13,003
    Location:
    Bedfordshire England
    I'd suggest a dewhurst switch but the sh prices seem to have doubled in a couple of years
     
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  3. ronan

    ronan Forum Supporter

    Messages:
    10,281
    dublin
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  4. brightspark

    brightspark Member

    Messages:
    31,770
    Location:
    yarm stockton on tees
    if its not broke don't fix it just put that switch in to a metal box with a blank plate on the front and drill it for the switch .a couple of quid
     
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  5. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    Is there no simple domestic toggle switch that will fit a normal single metal clad box? I keep all the switch gear mounted on the wall above the machine where I can’t accidentally knock it.
     
  6. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    Was just thinking that :D
     
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  7. Agroshield Member

    Messages:
    1,393
    And check the switch is earthed please.

    Right now, you have a painted metal box on a painted metal plate. And a metal switch on a ceramic backing plate. The box is probably OK as it will earth through the screws but the switch itself is not earthed and the knob could become electrified.
     
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  8. daleyd

    daleyd Member

    Messages:
    7,107
    Location:
    Wrexham, North Wales
    Looks like a 4 pole double throw switch - you could get a metal clad blanking plate and drill a hole through if you wanted to keep the same arrangement but it doesn’t look that great to be honest. I’d at least look at replacing the switch and add some hellermans sleeve or heat shrink over the soldered ends if you keep the same, or replace it with something a bit more substantial like a rotary switch/dewhirst switch type thing.
     
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  9. daleyd

    daleyd Member

    Messages:
    7,107
    Location:
    Wrexham, North Wales
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  10. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
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  11. brightspark

    brightspark Member

    Messages:
    31,770
    Location:
    yarm stockton on tees
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  12. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    Have given the very tired looking motor a clean up, while I was re-wiring. This doesn’t look right, copper washer over unused end of shaft between (home made looking) cover plate and inner bearing race. Will obviously pack it up with grease before reassembling, assuming this looks correct.

    3F002D09-0D5C-4A30-8DD2-1E3876B9BDD2.jpeg

    Can’t seem to find an assembly drawing online, it’s a Crompton Parkinson.
     
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  13. brightspark

    brightspark Member

    Messages:
    31,770
    Location:
    yarm stockton on tees
    is the copper washer a loose fit on shaft
     
  14. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    Yes, and there’s a light witness mark where it’s spun at some point against the alu cover
     
  15. brightspark

    brightspark Member

    Messages:
    31,770
    Location:
    yarm stockton on tees
    that's not good then it could contaminate the bearing. cant see the point of it serves no purpose
     
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  16. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,910
    essex england
    Sorry for thread hijack

    How long is a ml7 bed overall
    Thanks
     
  17. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    That’s what I thought, I’ll leave it out then, more room for grease

    the ways are 25.5”, overall length is 3ft.
     
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  18. daleyd

    daleyd Member

    Messages:
    7,107
    Location:
    Wrexham, North Wales
    I’ve got an old hoover motor on the bench, though a different make it’s very similar, I’ll take a look tomorrow
     
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  19. Ali

    Ali Member

    Messages:
    955
    Location:
    Cheshire
    Thanks, appreciate that.
     
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  20. Agroshield Member

    Messages:
    1,393
    A lot of this type of motor have one bearing fixed axially and one semi-floating (axially) to allow for heat expansion. Often the pulley end is fixed, so when you remove that end cap, the rotor comes with it along with the bearing the other end. If you remove the floating end end-cap, the bearing will remain on the rotor.

    There is often a wavy washer supplying some spring pressure against the outside race of the bearing.

    It looks almost as if this should be the arrangement in your one, but the wavy washer has been lost and the copper ring used as a substitute.
     
    Ali likes this.
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