Nip in a splice?

[TheTreeSpyder]

Do we consider a (hollow) splice to have a nip?

Or is nip more reserved for a pinching found more in a hitch(sheet bend) or even(vs.) shrinking collar(square knot) type mechanic in a lacing?



i see nip to reduce or terminate force flow thru a lacing;
as different than friction to reduce or terminate force flow thru a lacing.

[SS369]

Do we consider a (hollow) splice to have a nip?

Or is nip more reserved for a pinching found more in a hitch(sheet bend) or even(vs.) shrinking collar(square knot) type mechanic in a lacing?



i see nip to reduce or terminate force flow thru a lacing;
as different than friction to reduce or terminate force flow thru a lacing.

Good day TreeSpyder.

Interesting question.

I tend to think that the opening of a normal bury splice, that the tuck or bury goes through, as just the beginning (or end) of the enclosing sheath. Yes, it does nip in a fashion as the angular filaments attempt to straighten as the the tension increases, but not a nip as we've described in other knot discussions. The primary work is done by the whole of the encasement, little by little, with the forces spread along the length of the bury. The constricting force at that point of entry is no greater than the rest, imo.

I can imagine, though, that the constriction of this area can change and increase (or decrease) the grip there at times of angle differences, as in a ring load scenario, were it used in an eye configuration.

Now in the case to make for a Brummel type splice, I would say that it is most certainly a nipping area.

SS

[TheTreeSpyder]

i found this old pic. of the simplest (and least secure) of arraingmeants/lacing to hold a load.

To me it shows a basic hitch:
Full 100# line tension, travels a friction-ed route that gradually reduces the line tension.
A point of reduced line tension; is then 'pinched' by full line tension, creating a 'nip'; that 'holds fast' the line against the pull of the load.
 
A straight, buried (eye) splice to me; is more like so much overwhelming friction path(as you describe), it holds the load w/o nip?
Also, the hold of this splice is along the long axis of the line, not a pinching across the short axis of the line w/stopping force.

Yes, taken to Brummel, can see more 'pinch':
but if splitting hairs /fibers; the piercing thru the 'braids' of a Brummel to me is more of a mechanical 'staple'/pinning of parts w/mechanical stop not just pinch pressure. 
Like a cross stitch thru splice in whipping etc. as a stop:
This, does set tight and give pinch/ 'classic' nip with force, but then adds a (more secure) 'mechanical'/physical invasion thru the braid(changing/upgrading it's classification?).

Just seems best to accurately name and perceive these parts in the simplest/ rawest of patterns;
to then be able to command and call out the same base parts/modules as seen in more complex patterns.

To then, more intently lace/invoke named forces purposefully/most correctly at each point in the mechanic;
and add other line paths etc. as 'spice' to the recipe to suit various circumstances of usage, security, strength, angle, material etc.


 

[SS369]

Looking at the picture you provide, the "knot" (not the stopper) is more weave-like than knot-like, to me. Or parts of a braid.
And that is what I think splices of most kinds are, again, to me.
That's what a rope is as well.

It is the multitude of low angle crossings, wefts and warps, that add up to do the restricting of overall movement. That is also why the strength of these connections is so good. The lack of hard turns to inflict damage to the inner and outer fibers, whether in tension or compression, is the basis on what I am thinking.

So are there names for these places in a weave/braid group? Crossing strands?
How to designate the pattern of these because they don't have to be necessarily sequentially consistent?
Hmmm, I'll have to look into this.

SS

[TheTreeSpyder]

i see a (simple) Hitch.

Classically a Load hanging full tension on line leading to a friction path reducing line tension.
Then a reduced tension point,  pinched under a (preceding friction) greater full tension point; against hard, convex object (nip).

When, no hard convex object, must use hard tensioned line part to give nip.
Rope (webbing, chain, belts, cable, monofilament etc.); natively only supports/resists on the inline/ length axis, and only in the tension direction. 




These 2 pics here; show the line in the same path on each.  Only the load changes.
Depending on friction etc.; the 2nd pic might hold, might have to increase lesser weight etc.

They both work by pinch, after friction, but the 2nd pic uses a "3rd party" to maintain Load secure.
Would we call this pinch point on pic#2: Crossed Turn(?) a nip?

The lines have same paths, just the force flow direction thru that path is reversed.
To me; more than just the line path matters; so i'd only call the 1st pic a Hitch.

[xarax]

more than just the line path matters; so i'd only call the 1st pic a Hitch.

  Correct. I agree. When both legs are loaded, it is a nipping loop. When only the one/first leg is loaded ( the other/second leg being immobilized in between the first and the surface of a pole or another line ), it is a hitch.
   The problem arises in the "two half hitches". To me, the first knot is, in fact, a nipping loop, and only the second is a half hitch. If the first knot was a half hitch, meaning that its second leg would had been totally immobilized, i.e. 100% unloaded, what would be the need for a second half hitch ?
   Of course, in reality things are not so black and white. The second leg of the nipping loop of the bowline, the eye leg, is loaded with 50% of the load of the first ( the Standing End, which is loaded with 100% of the total load ). So, there is some "hitching" action there, too. Also, in the "two half hitches", the first hitch is not able to reduce the tension 100%, so a second hitch is required, indeed, and this reduced - but not 100% eliminated - load in the segment of the rope, the "bridge",  in between the two "half hitches", is what keeps them adjacent to each other.

[DerekSmith]

Hello TreeSpider, good to hear from you again.

I might have guessed that if anyone was going to open this can of worms, it would be your good self - you always look just that extra bit beyond the obvious.

The question then that few of us want to tackle is ' Is a splice a knot ?' (and following from this is 'Is a rope a knot ?'), because in many cases a splice is simply a rope of a different shape...

For me, the answer is one I don't think many of us want to accept, and that is - Yes, of course a splice is a knot.

Taking the case of the hollow bury splice into a braided rope, I think we can easily argue the case that it is a knot by pulling alongside a VT Hitch or the KC Hitch.  Both these hitches have a braided section which attempts to open under load.  Elongating the braid can only be achieved by a commensurate reduction in diameter, and this results in a 'nip' which in turn increases cord to cord friction.

Granted it is a complex 'nip' in that it is not a simple nip of a cord against itself, and it is not the tight round turn type of nip we as knotters are used to accepting, but it is a lateral constriction accentuating friction - it is a 'nip'.

Derek

[DerekSmith]

Two challenges in one here - 'Does the angle of the applied nip matter ?' and 'Does a non cordage component count as part of the knot ?'



So - 'Does the angle of the applied nip matter ?' and along with this 'Does the amount of rotation matter ?'

I would argue that it does not matter if the nipped line makes an angle of 120 degrees under the nipping line, or 90 degrees, or 60 degrees or even 30 degrees.  So long as the loaded line brings to bear lateral pressure (nip) on the nipped line it will create an accentuated friction point and so create the all important 'tail load' that will be amplified by the component capstan effects.

'Does the amount of rotation matter ?'  Well, it certainly matters as far as the amount of friction generated, a quarter turn will generate more friction than a tenth of a turn for the same rope tension, but the question is - are they both still 'nips'? - and I would argue that as they are both laterally applied pressure to generate friction, then yes, they are both nips.

As for the question 'Does a non cordage component count as part of the knot ?'  In the image example we have two chunks of non cordage.  Without them there would be a non-knot, so clearly they are part of the knot, and by the previous arguments, the end is very much 'nipped' by the loaded line.  If I make a Prussic around a stick or a loaded rope, both are part of the knot and both are being 'nipped'.

Derek

[TheTreeSpyder]

Hey Derek, good to read ya!

If a splice is a knot, it is a permanent type knot. 
Generally in working knots i look to craft a lacing to be undone, relaxed and ready for next adventure.  To me, part of the magic of a rope (as a device choice over wood/metal beams etc.) is the ability to use for holding, securing, transporting, positioning etc.; and return (and relax) line to unaltered shape when done without removing nails, filling holes, paste/weld back to original length etc.  So, i always looked at a permanent knot as an err, eye-splice etc. as another type of thing..

In a nip, i generally look for a an immediate stop/pinch thru the short axis of the rope device(pin by force not by physical device/staple/bar tack invasion thru line).  Whereby a splice usually pulls along the long axis of line gradually, more just surpassing loading tensions with accumulated frictions.  Any pinch might come thru the tight sausage bent back around to thread down it's own now overstuffed casing, but that is not immediate stop/ nor trys to be.   

A brummel adds another variety of stop, more of a weave/'staple' thru friction path w/perhaps dead stop of stopper/butaned bell swell at end to me.   i always think, that in lieu of a positive stop nip(like when just overcome by accumulated friction path in 'stuffed sausage splice' ); it is even more important to have a physical stop of stopper knot/bell and/or whipped bar tack stapling thru short axis of line at splice. 


i guess, buried we all have a favorite base, reference, simple rope construction/lacing/knot?  Mine is this hitch;  To me, the hitch as pictured shows high tension part (full load/full line tension part)easily pinching down on low tension part( at rope point after  friction path/turn reduces this part of line to lower tension force). The log here is a required firm, convex surface to nip/pinch against.   In a Bend, usually find each tensioned Standing Part as hardest surfaces to nip between, and highest tensioned pressure to do so with(so i see line as a replacement host/mount for log).

Naming correctly i think, important not just to communicate; but in usage to command/call out more precisely, correctly and confidently.  Saying to self, i'm building this part in, that has this characteristic that it will lend to this rope mechanic; it is most critical to watch this lacing deployment at point X etc.   Guess i not only seek to listen to the rope's secrets, but talk to it as well!!  (i'm knot schizo; and neither am i?)

[TheTreeSpyder]

  Correct. I agree. When both legs are loaded, it is a nipping loop. When only the one/first leg is loaded ( the other/second leg being immobilized in between the first and the surface of a pole or another line ), it is a hitch.

To me this 2nd lacing is a "crossed turn"(?) ; the 20# weight approximately inconsequential because might be enough friction to not need the 20# weight/ballast and/or free hanging weight of line could itself be 20# w/o needing 20# weight to hold the 500# load.  But, anyway; would the crossing, be called a nip; when the holding force is not the load, but rather this 3rd party, and even w/o 3rd party(20# ballast weight); the pinch is not this classic greater load tension securing self by sitting on less tensioned point(exact equal/ opposite of can't pick yourself up by own bootstraps scenario)?

[xarax]

  Correct. I agree. When both legs are loaded, it is a nipping loop. When only the one/first leg is loaded ( the other/second leg being immobilized in between the first and the surface of a pole or another line ), it is a hitch.

... the 20# weight [is] approximately inconsequential because [there] might be enough friction to not need the 20# weight/ballast and/or [the] free hanging weight of [the] line could itself be 20# w/o needing [the] 20# weight to hold the 500# load. 

   OK : if this load on the first leg is, indeed, sooo light, that it may even be redundant, the knot is a crossed round turn, a riding turn, and not a nipping loop. I made the distinction between the two general cases : first, when only the first leg is loaded, and, : second, when both legs are loaded, even if one is loaded by almost half the initial load ( as in the case of the nipping loop of the bowline ). However, if the first load is so small, we should better ignore it, as you say.