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Repairman's knot

Discussion in 'Electronic Repair' started by N Cook, Mar 27, 2007.

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  1. N Cook

    N Cook Guest

    For tying up mains leads on equipment, tight to the back of the chassis - is
    the knotting process described anywhere on the www ?
  2. Do you mean loom binding using waxed thread?

  3. BTW, your sig sep ain't correct.
  4. Ron(UK)

    Ron(UK) Guest

    It`s called a rubber band ;)

    Presuming you mean to get rid of excess length of cable when the gear is
    installed. Don,t coil the cable, zigzag it.

  5. I think what he means is something I was taught in electric shop in junior
    high school (1967?) called an electrician's knot.

    Here's a drawing of it:

    and a description:

    I've often cheated in places where the cable was already run and did not
    want to cut it to tie the knot by taking a large nylon cable tie (aka
    Tie-Wrap) and placing it around the wire inside the unit. Be sure
    to leave some slack so that if the wire is pulled it stresses the
    cable tie, not the wire.


    You are right about coiling the wire, it will create a magnetic field.
    The one exception to that rule is coax, it can be coiled.
  6. Ron(UK)

    Ron(UK) Guest

    If the OP meant to tie up the mains cable when transporting an item of
    equipment, say a vcr or tv, then the usual way is to coil a good portion
    of the cable closest to the appliance, then squeeze the coils together
    and wind the rest of the cable around that so that it resembles a
    hangmans noose. Then the outer loop of one coil is passed over the plug
    top to secure it.

    Or you could use a rubber band.
    Careful now... ;)

  7. That's the easiest way. I found that for items I do this with often,
    such as a laptop power cord, the best thing are nylon strips with velcro
    on them sold for lacing computer cables.

  8. N Cook

    N Cook Guest

    Not that one.
    For storing or just shelving unused equipment , so the mains cable was not
    trailling about and no need for ties of any sort. All the cable is taken up
    into the hank/knot leaving just the mains plug exposed and all tight up
    against the back of the chassis.
    The person who showed me years ago how to do it , went overboard.
    It used to annoy me that the bunching was so close to the chassis and
    bunched so tight you needed a screwdriver to open up the knot and there was
    always a tight spiral of cable for 6 or so turns when undone that stayed
    like that. I've long since forgotten how to do it.
    I invented my own that did not deform the cable so much and easily undone
    by myself or customers, but you cannot form it right up close to the
  9. Ah - know what you mean now. Those old enough to remember rope washing
    lines will remember they came like that too.

    But plastic cable ties weren't around then. ;-)
  10. N Cook

    N Cook Guest

    The person who showed me was ex-services WW2 or 1950s sparky.
    Yes really tight just like how plastic covered , corded washing lines arrive
    packed, but with the plug and "noose" spiralling taken right up to the cable
    entry point and not even any obvious starting point to undo it, let alone
    being so tight. I remember the final move was really forcing a final loop
    over or something.
  11. Ron(UK)

    Ron(UK) Guest

    N Cook wrote:

    Yeah, as I said earlier, you take one loop over the plug top.

  12. Arfa Daily

    Arfa Daily Guest

    Here's the one I was taught. Assuming that you are right handed. Zig-zag the
    cable in your left hand, starting up close to the equipment, and making the
    zig-zags about 8 inches. Make about 5 or 6 of them, which should have used
    up about 1/2 to 2/3 of a 'normal' cable length. Stop zig-zagging when the
    cable end, with plugtop, is away from you. Now take the remaining cable in
    your right hand, holding it close to where the zig-zagged piece is hanging
    out from your left fist, and take a single tightly pulled turn around the
    end, winding away from yourself. As you complete that first turn, angle the
    cable in towards your left hand, so that it crosses over the point where
    that first turn started from. This locks the turn in place, and now you can
    just go ahead and keep winding the spare cable around, feeding the
    zig-zagged piece out of your fist, as you go. If you've judged it right (
    years of practice ! ) You should get about 11/2 inches from the equipment
    end of the zigzags, when you have about 6 or 8 inches of cable left. This
    last piece of cable is formed into a squashed loop, and fed through the end
    loops of the zig-zags. It is then pulled back over the zig-zag loops, and
    finally, you pull on the plugtop, which pulls the last loop in nice and
    tight. This method is the neatest I've ever seen, and NEVER comes undone on
    its own, unlike attempts that I've seen many engineers make, to reproduce
    something similar. Where they usually go wrong, is wrapping in the same
    direction as they made the zig-zags, This fails to lock that first turn in
    place, so the whole wrap becomes loose and sloppy. It's a lot easier to do
    than describe, but if this is the standard old repairman's wrap that you
    were looking for, I'm sure it will come right back to you as soon as you try
    to follow this.

  13. Arfa Daily

    Arfa Daily Guest

    I've sent you some pictures of a wrap in progress. I have sent them to the
    same mail address that you post to this group from. If you don't get them,
    mail me with a different address.

  14. N Cook

    N Cook Guest

    A first time for everything. Worked out how to access the email bit of, pointless looking at spam otherwise.
    If it was you who uploaded 9M byte of file/s there it/they will be staying
    there, no broadband here.
  15. Sofie

    Sofie Guest

    - - - - - - - - - - - - - - - -

    and why is cargo send by ship and shipments by car/truck?

    and why do you park on driveways and drive on parkways?
  16. Radiosrfun

    Radiosrfun Guest

    Depending on where you live, this actually makes "some" sense. You "can"
    manuever in your driveway - but when you go out onto at least "some"
    parkways - they're so jammed - they're more like parking lots.
  17. Arfa Daily

    Arfa Daily Guest

    That's a pity as the pictures showed exactly what you were asking. Just as a
    matter of interest, if you are involved in commercial repairs, as you appear
    to be from your postings, how on earth do you get by in this day and age of
    service info only being available on-line in a majority of cases, without a
    broadband connection ?? With a dialup connection to the internet, you are
    walking with dinosaurs, as they say on the BBC ...

  18. Search for the UL knot.
  19. Arfa Daily

    Arfa Daily Guest

    If I'm reading him correctly Homey, that's not the knot (!) that he's
    looking for. I sent him some pictures of the one he wants, but apparently,
    no BB, so would take him about a week to d/l
    9 meg of photos... I'll perhaps put the pics up on a website somewhere so
    that he can see them, poor boy ... d;~}

  20. Still take as long to load. ;-)
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