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mechanical advantage

Discussion in 'Commercial Tree Care and Climbing' started by smith ferguson, Jun 10, 2019.

  1. smith ferguson

    smith ferguson New Member

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    I need to get a 3 to 1 advantage on my rigging line to reduce limb drop post cut. I have a 3/4 inch rigging line. The only hardware I have that fits a 3/4 inch rope is my pulley block that will be in use. Is there another piece of hardware I can use with a portawrap to achieve the 3 to 1 advantage or should I purchase another pulley. If so, which one do you recommend?

    Here is skip to minute 3:29
     
  2. BC WetCoast

    BC WetCoast Addicted to ArboristSite

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    You can use steel biners, but it's a pretty tight bend radius. What size branches are you cutting that you need 3/4" rigging line? Can you get by with 1/2" and get some 2" pulleys?
     
  3. AGoodSteward

    AGoodSteward Power Head

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    Use a pickup.
     
  4. CT arborist

    CT arborist ArboristSite Lurker

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    When there are options: place a block at the crutch and cut smaller pieces to be lifted by the groundman at the portowrap. Bigger limbs you can start practicing trying them at a point where the limb would hung almost horizontally. It's hard to get it right almost everytime. Or maybe use two rigging points?
     
  5. Groundman One

    Groundman One Star Gazer

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    Oh my... :eek:

    I'm not crazy about how he grabs the rope with his hands to keep the tension to reposition. That's bad in so many ways.

    We use a separate line on a separate attachment point to pull the rigging line that feeds into the porta-wrap. When you have the pull done, you lock off the rigging line on the porta-wrap and then release the tension on the separate pulling line. You are always secure that way.

    Doing it by hand like that with one line gets your fingers in a tensioned rope and you risk injury and losing control of the load. Maybe both at the same time. Not to mention what the consequences might be for the climber.
     

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