Author Topic: Knot wanted  (Read 13096 times)

DerekSmith

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Re: Knot wanted
« Reply #15 on: April 28, 2010, 01:26:24 PM »
Sounds like the perfect job for small bolts & nuts (washers optional).  

My thoughts exactly or if you wanted to go with a non comercial option you could use wood dowels with a small hole for another pice of wood (sort of loke a cotter pin)


Except that I'm thinking Derek was trying to point out the structure, due to it's nature is going to have some flex and bend to it naturally, more so under various environmental forces. In such a case, a flexing connector is going to be more desirable since it can essentially take most, if not all of the tidal nature of the forces at play, with little effect on the the more rigid members.

Indeed Rrok007, flexibility is an important part of final load equalisation as the structure settles to share out the forces.  But the point I was (poorly) making in issue three in reply four, was relating to alignment rather than flexibility.

It is perhaps not readily realised that the lattice spars are rigid and do not bend as the lattice is formed into the curve of the round wall.

The force model of the Yurt has essentially only three components - A roofing spar, a pair of lattice spars making up an 'A' frame, and the girth cable.  The roof spar takes the weight of the roofing, the rain, snow and wind and translates it into two forces at the top of the 'A' frame, one force pushing outwards which is resisted by the girth cable (and translated around the Yurt to cancel out the equal and opposite push on the other side of the circle, the second force is downwards and is taken by the two legs of the 'A' frame down to the ground.  Side forces (wind pressure) are met by the leg of the 'A' frame op0posite to the direction of the side force.  Because the Yurt is round, it does not matter which direction the wind side forces come from, there will always be 'A' frame legs bracing against this force.

In order to take the weight of the roof and the sideways forces, the bracing 'A' frame legs must be straight.  If they are bent, then the force through them is likely to increase the bend and eventually snap them (the covering is believed to play a part in bracing bent loaded spars).

In order to stay straight, yet also follow the curve of the building, the lattice spars are stood at an angle to one another.  On a large diameter Yurt, this angle is not very large but on say a 12' diameter Yurt with 5' high walls, the spars of an 'A' frame can be at more than 30 degrees to one another.  This means that a hole straight through one spar will be out of alignment with the hole straight through the second spar by the same amount.  A rigid pin through these holes would either snap, bend, snap the spar, or rotate/bend the spar, while a simple cord lacing would easily take up this turn one spar to the next.

The side walls of the Yurt are a very special shape - they dish inwards.  This might look like the spars of the lattice are bent, but if you look carefully or take a straight spar and hold it against a lattice spar, you will see that the 'A' fram spars are all straight from the point of loading right down to the ground.

Derek

roo

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Re: Knot wanted
« Reply #16 on: April 28, 2010, 03:08:09 PM »
These are sometimes used, but there are a number of problems:

1  Not flexible, I'm using roundwood poles ie. tree branches. There needs to be some give to accomodate irregularities in the wood.
2 The structure is to be covered in cotton canvas. Metal fixings could cause wear to the cover.
3 Rust staining to the cover
4 Cost of stainless fixings

The dowel option is interesting but there is no flex and I think it would stick out a lot and potentially wear the cover.

 ???  I have never seen a trellis covered in canvas.  Are you sure it's a trellis?  The second oddity about using a cord with major cotton components on a trellis is that cotton readily rots!

Why must the connection be flexible?  I thought you wanted solid clamping.  Why not just drill a clearance hole through one of the rounds and sink a coated deck screw through the clearance hole and into the second member, where ever it happens to cross?  There will be no protrusions.



 
« Last Edit: April 28, 2010, 03:16:07 PM by roo »
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Justin

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Re: Knot wanted
« Reply #17 on: April 28, 2010, 03:50:56 PM »
Roo its not just a trellis it is the wall to a yurt

http://www.yurtshop.co.uk/yurts.html
Justin

roo

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Re: Knot wanted
« Reply #18 on: April 28, 2010, 05:02:30 PM »
Roo its not just a trellis it is the wall to a yurt

http://www.yurtshop.co.uk/yurts.html

If that is the case, then it is not a trellis at all.
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Dan_Lehman

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Re: Knot wanted
« Reply #19 on: April 28, 2010, 08:08:37 PM »
Roo its not just a trellis it is the wall to a yurt

http://www.yurtshop.co.uk/yurts.html

If that is the case, then it is not a trellis at all.

Someone needs to try "Google (trellis wall)" or Webster's 3rd New International Dict. among others.

To further add to the tactic of joining two cylinders by means of some
cordage through drilled-diameter holes,
let me muse (more timid than suggest, even, let alone recommend!)
about orienting the drilled-diameter holed in parallel planes -- so that
the (no necessarily so constructed?!) ring of cord would now equally
span the distance between poles/holes on either side!?  And the two sides of
cord would be equally taxed, pulled between an underside & upperside hole;
tightness with pole (collapsed) in parallel relation would become tighter upon
opening them -- and one might expect such a ring tied in usual materials to
accommodate such tightening rather nicely.

Length of material for the initially envisioned stopper-2-stopper, like a bolt,
securing is 2D + (stopper-1 + stopper-2);
that for my earlier-suggested (I was bold then) ring that ran through the
holes oriented in line and then around one side is 3D + piD/2 + bend ;
and that here meekly mused is 4D + bend, a tad less than other ring.

Now, as for the joining knot, I have a better recommendation, which is
to essentially make a bend of Ashley's eyeknot #1029 (which Budworth
later calls a "Tricorn Loop"; this I think can be tied pretty tightly and
efficiently (of both material & time/effort)  --tying the Overhand with
a short (wasteless) end around a big (for adjustment) bight, tight,
and then pull ring to desired tightness via bight leg, and then pull
the other bight leg to lock tied, and cut off end.

Again, part of the appeal I see in using a "ring" vs. "bolt" of cord
is the ability to re-position the cordage and thus put new parts
at the hole-end wear points.

--dl*
====

KenY

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Re: Knot wanted
« Reply #20 on: April 28, 2010, 09:21:57 PM »
Redbugg444
One of our Guild members was sleeping in a yurt only two weeks ago, and he has some photos of the inside I shall try to get hold of some if that is of a help.
I am curently hunched over a netbook, when I get home I shall get on the case.


KenY.

roo

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Re: Knot wanted
« Reply #21 on: April 28, 2010, 10:20:20 PM »
Roo its not just a trellis it is the wall to a yurt

http://www.yurtshop.co.uk/yurts.html

If that is the case, then it is not a trellis at all.

Someone needs to try "Google

Main Entry: 1trel?lis
Pronunciation: \ˈtre-ləs\
Function: noun
Etymology: Middle English trelis, from Anglo-French treleis, from Old French treille arbor, from Latin trichila summerhouse
Date: 14th century
1 : a frame of latticework used as a screen or as a support for climbing plants
2 : a construction (as a summerhouse) chiefly of latticework
3 : an arrangement that forms or gives the effect of a lattice <a trellis of interlacing streams>


Even if you resort to the second definition, it's no longer chiefly latticework if it is sheathed over with canvas.

Tell me; how many pages do you have to go through on a Google image search of "trellis" before you get to anything serving as support for wall sheathing?
« Last Edit: April 28, 2010, 10:26:02 PM by roo »
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DerekSmith

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Re: Knot wanted
« Reply #22 on: April 29, 2010, 08:52:10 AM »
snip
1 : a frame of latticework used as a screen or as a support for climbing plants
2 : a construction (as a summerhouse) chiefly of latticework
3 : an arrangement that forms or gives the effect of a lattice <a trellis of interlacing streams>[/font][/color]

Even if you resort to the second definition, it's no longer chiefly latticework if it is sheathed over with canvas.

snip

Yes it is - if you are on the inside - there is a beautiful latticework effect.

But to make the point again - there are two types of lattice...

The is the flexible flat lath type - typically sold at B&Q to train your sweet peas up, and being used ever more often in some of the commercial Yurts we see.  Lets hope these either get a lot of support from their coverings or that they never see any weight of snow etc.

Then there is the straight spar type which exhibit the slight dish in the sides to allow the spars to remain straight and strong.

They both have a 'lattice effect', but one is a building structure of extreme strength, the other is a visual effect as a screen or for lightweight plants to grow up.

Use it as a structural element at your peril.

Derek

Dan_Lehman

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Re: Knot wanted
« Reply #23 on: April 29, 2010, 04:36:00 PM »
Roo its not just a trellis it is the wall to a yurt

http://www.yurtshop.co.uk/yurts.html

If that is the case, then it is not a trellis at all.

Someone needs to try "Google

Main Entry: 1trel?lis
 ...
Tell me; how many pages do you have to go through on a Google image search of "trellis" before you get to anything serving as support for wall sheathing?

Perhaps you should NOT PASS GO, and instead of truncating my
words, heed them -- I said:  Someone needs to try "Google (trellis wall)"

And you get it all on page one, though perhaps you could go many
pages beyond, if feeling frisky.

 ::)

Justin

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Re: Knot wanted
« Reply #24 on: April 29, 2010, 05:28:42 PM »
WOW that is allot of heat for such a small thing lets all back up and cool down its a stupid thing to argue over
Justin

roo

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Re: Knot wanted
« Reply #25 on: April 29, 2010, 06:01:45 PM »
Roo its not just a trellis it is the wall to a yurt

http://www.yurtshop.co.uk/yurts.html

If that is the case, then it is not a trellis at all.

Someone needs to try "Google

Main Entry: 1trel?lis
 ...
Tell me; how many pages do you have to go through on a Google image search of "trellis" before you get to anything serving as support for wall sheathing?

Perhaps you should NOT PASS GO, and instead of truncating my
words, heed them -- I said:  Someone needs to try "Google (trellis wall)"

The OP said trellis.
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KenY

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Re: Knot wanted
« Reply #26 on: May 01, 2010, 04:25:39 PM »
As Promised,

Text and photos from a knot Tyer who lay in a yurt contemplating the walls.

Ken,
These are pictures I took on a previous visit to the yurt.
As far as I can make out they just did a thumb knot on each side of the cross-over on the lattice slats.
In nomadic use sections of  the lattice will just be squashed up into manageable bundles so the knots are not undone and a thumb knot is very easy to re-do should it come apart.
If used for a more permanent structure I would try a figure 8 on the side that touches the walls and use a thumb knot on the inside as it is easier to pull tight when in place. .
The cord in the pictures is nylon but originally was probably leather or rawhide.  A thumb knot would tighten up and be hard to undo so the simple answer would be satisfactory.
Hope this helps.
Isn't it strange how things appear just when you need them.
If he means the door hinge then anything will do as they had a wooden frame and a wooden door so the hinges used are the same as an ordinary door.
There is also a 'knot of life' which would be tied around the door in a symbolic manner but I would keep quiet about it as the book with the picture is almost impossible to dig out in under two weeks.

Hope these help

Ken

redbug444

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Re: Knot wanted
« Reply #27 on: May 04, 2010, 11:06:41 AM »
The second oddity about using a cord with major cotton components on a trellis is that cotton readily rots!

You know i've come to the conclusion that this isn't the ideal cord myself and bought lots of 550 nylon paracord instead.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380150937670&ssPageName=STRK:MEWNX:IT

Anyone want to buy 99m of light blue polyester covered cotton cord cheap?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170426833991&ssPageName=STRK:MEWNX:IT

redbug444

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Re: Knot wanted
« Reply #28 on: May 04, 2010, 11:11:42 AM »
As Promised,

Text and photos from a knot Tyer who lay in a yurt contemplating the walls.

Ken,
These are pictures I took on a previous visit to the yurt.
As far as I can make out they just did a thumb knot on each side of the cross-over on the lattice slats.
In nomadic use sections of  the lattice will just be squashed up into manageable bundles so the knots are not undone and a thumb knot is very easy to re-do should it come apart.
If used for a more permanent structure I would try a figure 8 on the side that touches the walls and use a thumb knot on the inside as it is easier to pull tight when in place. .
The cord in the pictures is nylon but originally was probably leather or rawhide.  A thumb knot would tighten up and be hard to undo so the simple answer would be satisfactory.
Hope this helps.
Isn't it strange how things appear just when you need them.
If he means the door hinge then anything will do as they had a wooden frame and a wooden door so the hinges used are the same as an ordinary door.
There is also a 'knot of life' which would be tied around the door in a symbolic manner but I would keep quiet about it as the book with the picture is almost impossible to dig out in under two weeks.

Hope these help

Ken



Thank you. Very interesting.

redbug444

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Re: Knot wanted
« Reply #29 on: May 04, 2010, 11:15:12 PM »
Ok

I've had a play around; I've got myself some new cord and this is what I've come up with.

For the 1st tied knot Ashley's stopper works well (thanks Dan). Easy to tie near the end of the cord and big to stop it pulling through.



And for the 2nd tied knot how about a thumb knot with a half hitch beneath it to take up the slack? Would this be stable do you think?