Author Topic: Construction Knots  (Read 14584 times)

rosco rathbone

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Construction Knots
« on: September 30, 2006, 07:34:59 PM »
I'm always looking for better ways to tie knots on the job. Yesterday, I had to tie a tagline onto a thirty-foot Ibeam as a "holdback" to control it's swing as it was raised from the floor out into an elevator shaft-the center of gravity was about 20 feet from where the beam was sitting as the electric chainfall started to raise it, so I took a round turn on the picking eye welded to a man-lift. The problem was that I had used a running bowline to form a quick noose and it slipped right off the end of the beam since the direction of pull caused the beam and the tagline to be parallel.

What would a tighter gripping knot have been? Timber hitch?

DerekSmith

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Re: Construction Knots
« Reply #1 on: September 30, 2006, 08:14:49 PM »
Try the KC hitch as described in http://igkt.net/sm/index.php?topic=542.0

It's very quick to tie/untie and can grip a taper.

Derek

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Re: Construction Knots
« Reply #2 on: October 01, 2006, 01:41:42 AM »
  ;D

i think that part of the problem here is that the Load / host device that you are placing rope around is not convex; and has no imperfektions to dog rope into/against.  A spar is round, so can push out evenly against rope in all directions; has texture and mounds for tightly choking line to hang up on.   Even a square cant as a shape can't be capitalized on for rope to grip; let alone I-Beam.

Perhaps a half hitch preceding the bowline could have saved the day.  Better yet, running bowline to other side of choke on beam, lift cable etc. lifting beam (or other positive place to lock bowline/ running bowline to); then in the bight slip 1 or 2 preceding half hitces on the end wanting to tag from.  Think of getting positive lock from 1 position of line (bowline, snap, hook on end to positive pull point on beam/ lift system) and steering from the other point; to split and specialize these tasks.  And also give the security of 2 grab points on Load.
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PatDucey

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Re: Construction Knots
« Reply #3 on: October 02, 2006, 12:43:34 AM »
If you have enough length in your tag line, you can tie it off at the headache ball (I'm sure there is another name for the headache ball, but I don't know it) and throw a couple of half hitches around the end of beam.  As long as the pull is at an acute angle, the half hitches will not slide.  You can leave the tag line attached to the headache ball for the next lift.

I have also seen tag lines attached to a load with a C-clamp.  I was worried that the clamp could come loose and turn into a missle, but it never did. I'm not sure what OSHA would say about that.

You can also tie a constrictor around the beam and a couple of half hitches toward the direction of pull.  As long as the "business part" of the constrictor is on the flat of the beam, it should hold reasonably well.  The half hitches will work to reduce the pull on the constrictor when the beam swings.  A constrictor alone could capsize without the added help of the half hitches.

Patrick

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Re: Construction Knots
« Reply #4 on: October 02, 2006, 08:26:02 AM »
Hi Pat, and all,
I too have seen G-clamps used on an RSJ (as I beams are called here), but my solution would be to use the Double Overhand Noose (aka Poacher's noose, etc) as a guide line attachment - pulled up tight, even round square objects, it jams up to form a firm grip, but by pulling on the knot you can remove it quite easily too.

Gordon

knudeNoggin

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Re: Construction Knots
« Reply #5 on: October 02, 2006, 04:31:44 PM »
... so I took a round turn on the picking eye welded to a man-lift.

That sounds like a secure, easily tied to point, but apparently not or it's not on the object beam?

Quote
The problem was that I had used a running bowline to form a quick noose and it slipped right off the end of the beam...
What would a tighter gripping knot have been? Timber hitch?

You haven't told us what type of rope you employed, but it would probably work if you
tied some tight noose and followed that with a half-hitch (or two); the half-hitch(es) will
give some frictional resistance to being pulled along the object, to which the grip of the
tightened noose should prove adequate to arrest movement, especially where you are
just guiding and not hoisting the object.  (The half-hitch might be tied first but with a long
enough end to then tie the tight noose, say, a turn & clove hitch to the line (aka Two
Half Hitches).)

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KC

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Re: Construction Knots
« Reply #6 on: October 02, 2006, 04:57:37 PM »
i took the round turn to be the control position; not on the load?

i think the solutions run the base pattern of anchoring end with noose around etc. or hooking to solid eye/ clamp/ hitchpoint/ lift cable etc.; then preceding that anchor with a half hitch(or 2) to direct /tag Load from.  The anchor strategy at end giving security, 2nd grab and a keeper on half hitch.  The half hitch giving another hitch point, and where rig steers from. 

Previously he tried a running bowline to be anchor and steering component in one; these strategies divide these duties giving 2 contact points; an anchor on more positive position, and a very adjustable steering point.  If beam was very vertical; night have to give another pereceding strategy to keep half hitch from sliding down towards anchoring strategy; especially when Standing Part is perpendicualr to Load.

i'd still use similair 2 part strategy on a round, textured spar; but especially here with slick(?) beam; that is not round/ has concave parts that the hitching(s) don't fully contact all the way around to grip securely.

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We now return you to the safety of normal thinking peoples.
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drjbrennan

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Re: Construction Knots
« Reply #7 on: October 02, 2006, 07:43:10 PM »
I did some experimenting with the 'KC Hitch' today, on broomsticks and aluminium bars, and from the first try it performed very well. Easy to tie and cast off, with little adjustment needed for a ratchet-like grip. It's definately in my list of favourites now. ;D
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KnotNow!

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Re: Construction Knots
« Reply #8 on: October 03, 2006, 03:41:17 AM »
Hi Rosco and All,
  Why bother.  You have some sort of eye for the "picking hitch".  Tie the tag line there and run it out the beam to near the end and toss any hitch of your choice near the beam end.  It can't slide off the end as it originates at the lifting eye so half hitch, or whatever hitch works fine.  Have I missed the point of the rigging?  If I hitch a hand line to the beam at the lifting point and run it along the beam to the swinging end and there place any hitch... half, clove or any other to keep my line from walking off the end of the beam..  Why must my hand line need to not slip?  Hitched to the lifting point it can't run off the end of the beam.  Please, if I am lifting stupid inform me.  My rigging of this lift isn't needing icecle or anyother.  Rig it your self as I suggest, then argue.
  Not to say that KC hitch will not hold on a beam or a pole or a spar.. but if there is a lifting point why not run the hand line from the lifting point out on the the beam or spar and then add a single hitch so you can turn the beam or control the lift?  Just a dumb comment from a landlubber.  Forgive all offense.
« Last Edit: October 03, 2006, 03:45:02 AM by KnotNow! »
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Re: Construction Knots
« Reply #9 on: October 06, 2006, 04:54:43 AM »
Hi Rosco,
  I can't find a way to quote from your earlier post but you said "so I took a round turn on the picking eye welded to a man-lift".  I took that to say that there is an eye on the beam or some sort of lump welded to the beam.  So my lack of high steel terms may have gone off thread.   Since no post have come since that fateful day... I'll open it up again.  I want to read about what works.  I am with Patrick D, I use C clamps and I also use (trade name) Vise Grips.. the bigest size.  Ain't dropped nothing yet.  It takes very little purchase to help a line from sliding along a beam or a pipe or a spar.  I use a plaited tail on my blocks and it grips like the very devil  Tarred and sticky, compressing and gripping.. no nails needed.
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rosco rathbone

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Re: Construction Knots
« Reply #10 on: October 13, 2006, 11:03:17 PM »
Hey guys

Almost every suggestion in this thread would have worked better than what I actually tried. As a matter of fact, I ended up just going to the truck and getting a big ass bridge clamp and cranking it down on the end of the beam and then tieing the tagline to that (there were no lugs, bolt holes, or anything else to tie to). But that is a very very inelegant solution.

Now that I think about it, a bowline to the choker with a half-hitch near the end of the beam would have worked well. Or even a stopper hitch or constrictor hitch broken at the right point, and then a half hitch as above.

Ok , here's another one for you. Two actually:

one: working on a suspension bridge job, I had to bend two ends of a long line together that was going over a well wheel 150 feet up at the top of the tower. I used a reef knot and now realize that I made a serious mistake. What's the best knot for this? It needs to be able to carry at least 100 lbs of load.

two: What knot would you use to tie a sheet of plywood to a "tail" hanging from the knot in a well-wheel loop. No clamps. I always used a big clove hitch and tried to break it at the edge of the sheet so that it would "bite" like a choker, but there must be a better way.

squarerigger

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Re: Construction Knots
« Reply #11 on: October 14, 2006, 12:47:24 AM »
Hi Rosco,

A well wheel - could you describe what this is please?  I suspect I know, but I would just as soon not assume.  Does it have a rim with any kind of a groove in it such as a sheave would have?  As for the load the knot/bend/hitch/splice can carry, that depends on the strength of the line, the ability of the tyer and, of course, the type of knot/bend/hitch/splice.  If the knot/bend/hitch/splice reduces the strength of the line by 50% say, then the strength of the line has to be at least 200 pounds SWL or at least 1000 # BS if the line is brand new.  Some knots or bends may be stronger than others (here I assume that "strength" refers to ultimate tensile strength at breaking) and some splices may be better suited than others.  Question 2 - what is a "tail" , why is it there, how does it fit into the well wheel loop, what is a well wheel loop, and does the sheet of plywood have dimensions (length, width, thickness, density) to it, or even any hole in it?  Does the sheet of plywood exist as a single sheet or is it one of several pieces?  Is it subject to windage?  Lastly, how thick is the line and is it made of a specific material?

Yeah, questions, questions - still, it never hurts to clarify!

Lindsey

KnotNow!

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Re: Construction Knots and a well wheel.
« Reply #12 on: October 14, 2006, 07:02:48 AM »
Hi Lindsey, I think a "well wheel" is a single block with a skeleton cheek.  I won't know if the poster will not come back.  This block has a very large shiv and a "cheek" made by casting or other method so it is at clock points of 9, 12 and 3.  Just enough to keep the line from running off the block.  It is also of large diameter 12 to 24 inches, most usless on ship board but good for a construction site.  This helps it to have very low friction at the bearing and almost no friction in the line. It is a single block to be hung for the lifting of easy materials.  Yes, you may  pull the down haul and then say "easy" but then I've been there and done that and construction work is easy until you do it.
  So I may be all turned about as we never called it "well wheel" but I think this is the block that is refered to.  Or not.  Today, to move much wood, we used the bowline and the timber hitch (tied on a bight).  Tomorrrow all  wood will be moved by hand or in slings.  One huge maple may be felled with a hand line up about 25 feet for useful stress to the safe side, and then brought to earth to miss the barn and the pump house.  Might fall fine but I am the fellow with suspenders and belt.  Twice protected, once saved.  You want less for your barn?
  I hope the orginal poster (Rosco) comes back with "well wheel".  Reason I think that I know is I also hand dug some wells and we had a single block hung at the top to haul up dirt.  Darn I am old and have done too much digging of wells.  So putting shingles on the roof or buckets of dirt.. there is a use for the single block and all of them (in my past) where large in diameter (maybe 12" to 16" or larger) and had "cheeks" at the 9, 12 and 3, as I said.  All were built for 3/4 or over line.  I think I may change my handle from KnotNow to "This Is How We Did It!"  cheers!
  A day later.. no less smart and most surely no less stupid.. When I wrote, "make a sling".. I intended it to be from a different rope.  Not the lift or fall from the well wheel.  I think the well wheel name migrated from the hole in the ground to the construction industry and then to this century.  Still a good gadget.  However using the line in the wheel as part of the sling needs to come up a century or two.  A "purpose made" sling for the 4x8 will save much time (make several so workers on the ground can strap up some loads before and workers in the air can toss down empty slings).  OOps. Sorry Osha.. Slings can be returned to ground on the tail of the "well wheel" rope.  No tossing of slings will be accepted.  I could be all full of rose fertilizer.  I have my old well wheel, which we used for 40 years to bring shingles or tar or whatever to the roof or dirt from a hole (how I hate digging) and it is on a swivel hook and therefore has a bar at 12, it also has one at 9 and 3 but is open the rest of the arc.  The shiv accepts 1" and it is plain bushed.  With good lubrication and 3/4" line it runs as if it were friction free.  Still using it after all this time.  But I am a Lubber and know very little about anything else.
  I'll tell you that modern plastic line is changing my world.  I'll be using this 7mm stinkum cord we bought instead of 3/4 manila.  My new (not to be made yet or even fully designed) "well block" will be ball or roller sealed bearing bushed, just right in diameter for not stressing 7mm as it bends on the shiv and will last me to the end.  Come to think of it... the old block may do that, with no modification.  Almost 150 years of good service.   yeppum, I know, you folks on the other side of the pond think of 200 years passing as a walk in the park and a quick lunch.
« Last Edit: October 17, 2006, 06:00:54 AM by KnotNow! »
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rosco rathbone

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Re: Construction Knots
« Reply #13 on: October 16, 2006, 12:23:35 AM »
Hey guys

Yeah, the well wheel is just a single sheave in a bracket or hangerr, not sure what you call it. You hang it on a choker over a beam and You tie a line in a big loop and leave a long piece of line hanging out of the end of the knot-that piece is what you use to tie onto whatever load you have. Regular manilla rope, 3/4 diameter approx (sorry, I don't know jack about rope--something else I need to learn). The knot never goes over the sheave-it wouldnt fit.

I;m just talking about one or two sheets of standard plywood, 4x8 or whatever. I would just tie the tail around them in a huge clove hitch. No clamps, no holes. Subject to a good deal of wind--this is way up in the air over a river, going up 100 feet.

Also, reef knot can't have  been the right knot to tie in the loop going over the well wheel.

KnotNow!

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Re: Construction Knots
« Reply #14 on: October 16, 2006, 03:24:02 PM »
Hi Rosco,
  I think I see what you are dealing with (a dumb boss).  How hard would it be to make a sling for the one or two sheets of 4x8?  I think keeping the load separate from the haulage might make everyone a bit safer.  Of course you may not have much choice as somebody tells you jump and you must say "how high?".  The "well wheel" has been with us for many thousands of years and so has the boss who says "do it".  If you and I were working at my home site I'd work up a simple sling for the 4x8 and attach the fall from the well wheel for each lift.   What we use here, at my home, is a sling with spliced eyes to the corners of the 4x8, a siezed eye at the lift point and a smaller "cat line" to keep the sheets from coming adrift.  Now how to suggest to the boss that this is better... Oh Well.  I published a sling for 4x8 in Knot News some time past.  I was slipping the sheet up a ladder and then into place.   I needed to follow the sheet up the ladder and then be able to disconnect, one corner at a time.  I used a sling with  hooks.  My roof is an 18 pitch.  All the roofing is on.  I did not get killed.  Alice still loves me.  Must have worked?
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