Author Topic: Which way is the true sheet bend?  (Read 8440 times)

KC

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Re: Which way is the true sheet bend?
« Reply #15 on: September 09, 2016, 09:40:29 AM »
Is this something you have tested and prove 

No sir; i'm sorry  this is simply what i've always seen handling it and making sense out of lessons handed down.
This is why i didn't reply at first here or other places.
i always thought and felt, of course 'Leftie' isn't as secure;
it mechanically can't be.
.
Sheet Bend doesn't have the Nipping Loop - pulled from what would be the eye side
BUT, same loop would be pulled from it's S_Part;
but any way it doesn't seem to be the side trying to walk off the job;
As it forms a Hitch, it's Bitter End is sitting on one of the hardest surfaces to Nip proper.
Bight side seems the escape side,  not forming a Hitch lock/ not crossing turn nipped by self.
.
To me, they are visually similar, forces do run different loading patterns ;
but still just as the look similar, each has an escape side, and a lock side;
and depends on line tension and hard surfaces as Nipping tools, like any other.
.
So i think, to Nip against the hardest surface, Bitter End of escape/Bight side
must follow into hardest S_Part line
As GREEN Bitter End seats to BLUE S_Part
But, PURPLE Bitter End evades this hardest Nip, by turning away from it.
.
Orange side of eye forms a Hitch on own,
Green side of eye forms Bight w/o hitch, so is focus of trying to 'nail down'.
My eye simply doesn't expect as much Nip on leftie, tried to reveal this with the colors.
« Last Edit: September 09, 2016, 10:40:40 AM by KC »
Rope-n-Saw Life
"Nature, to be commanded, must be obeyed" -Sir Francis Bacon
We now return you to the safety of normal thinking peoples.
~ Please excuse the interruption; thanx -the mgmt.~

Dan_Lehman

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Re: Which way is the true sheet bend?
« Reply #16 on: September 10, 2016, 04:17:10 PM »
Quote
With what rationale(s) --for the recommended cable clamping,
and its relevance to the eye knot?

What eye knot?
Ah, the one made w/cables, and your mention of the
*bowlines* paper.

In any case, IMO the (never stated?!) rationale for the recommended
clamp the U-bolt-into-cable-TAIL orientation is that the U-bolt
will physically deform the material somewhat, will grip it thus
more tightly & harmfully, and so it's best to leave the SPart
running between tail & broad base of the clamp --and any
slippage will be of SPart slightly out of this until clamp
nearest eye abuts the eye/object and we'll hope then
that slippage is arrested.
(Note that the quoted source above mentions "strength"
vs. security, so my musing about slippage is probably
much into fantasy.)

In tying the multiple Lapp bend, I do find it best that
the "hitching" line run around to nip hard/first into
the tail; it slips more readily otherwise.


--dl*
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KC

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Re: Which way is the true sheet bend?
« Reply #17 on: September 14, 2016, 12:46:25 PM »
theories:
ropeClamp rule of thumb:
If U bolt is on S_Part side / before frictions around eye, can drop efficiency 40%.
So i always remember 'saddle to solid'.
.
Once again 'pure inline' mantra of not deforming the single loaded leg S_Part for most strength;
(besides next step of providing another leg of support for load sharing)
and Nip  after frictions, on hardest surface, with greatest force for most security.
(usually giving deformity to bury in lacing for most inline support).
.
Cable like rope is maid to be loaded only on the inline axis, and only in tension direction.
(inline axis is the major axis of a device{log, rope, etc.),
whereby forces on inline axis only can leverage across the short axis/minimal
>>cross-axis would be narrow axis across length of device, allowing major axis to then be leverage-able.
>>only across center of perfect circle, would present no axis more leverage-able than other axis)
lines(cable/rope/chain) only have so much tensile, and only support load on inline axis
>>any cross axis/deformations from inline leverage load force higher in line,
>>leaving less usable tensile to support 'nominal' load.
.
But,
The stiffer line placed into rope model, the more sensitive to any deflection from inline.
Thus, cable is most sensitive to breaking/bending 'pure inline' mantra.
Cable even takes larger diameter pulleys for same diameter line, and sheave specially shaped to support 'belly' of cable.
All, because cable is stiffer than rope, so is more leverage-able on cross-axis, to raise tension in line more,
>>to ultimately leave less of line/cable absolute tensile strength remaining;
>> for the relative tensile strength (inline) to support/resist load
Rope-n-Saw Life
"Nature, to be commanded, must be obeyed" -Sir Francis Bacon
We now return you to the safety of normal thinking peoples.
~ Please excuse the interruption; thanx -the mgmt.~