Why do some scale rope unravel and others don't

[twintrow]

Why do some ropes need to be tied, glued or burned to keep from unraveling, and others do not.

 

Seems most of the third party rope makers (as opposed to the rope in kits) have this issue.  Morope does, the rope from Jerzy Bin did as well.

 

Not sure about Chucks, does it also?.

 

But seems most all the rope in kits does not unravel......why is this?

 

Since I will be making my own, I'd like to find out if I can avoid the unraveling issue.

 

thanks

Tom

Edited December 30, 2013 by twintrow

[SailorGreg]

Any laid rope, scale or fullsize, will unravel if cut and left to its own devices. Some will do it quickly, some will retain its shape for a while but will not need much encouragement to unravel. It depends on various factors such as the inherent stiffness of the yarn, the tightness with which the twist was put in the individual strands, and the length of time since the rope was made. I guess kit rope will have often been made some time ago and probably from lower quality (and perhaps stiffer) yarn - it will tend to keep its shape fora while when cut. The "quality" ropes were probably made shortly before you receive them and probably use softer yarn to give a more realistic feel and look.

 

I would treat any laid rope to stop it unravelling when cut because even if it looks good wen you cut it, it might not look good tomorrow.

 

Greg

[Chuck]

The plastic stuff in kits is treated and thats why it wont unravel.  Same is true for the natural stuff.  But not all laid rope will unravel.  If properly hardened after laying it up it certainly wont unravel.  My rope wont unravel at all.  If you use a sharp...sharp blade this is especially true.  Using a dull blade may make the ends start to frizz up a bit.   My larger ropes may unravel a little bit,  but not too much.  I have since created a method to ensure that doesnt happen.

 

The smaller sizes will not unravel at all....The key is getting the opposing tensions in balance.  If you dont wind the three strands initially enough times then it is most likely the final rope will unravel.   That is usually the mistake that is made.   When I first started making rope,  that was the case.  But I kept increasing the amount of twist in the initial strands until I was doing it four times as much.    Each time I increased it....the rope unraveled less.    Also remember not to over twist all three strands together.  That will cause kinking in the final rope.   You must through trial and error strike the correct balance in the tension.

 

Chuck

[druxey]

Chuck is absolutely correct in his assessment.

[Chuck]

Thank you Druxey.   I just made some .062 rope yesterday.   So I just ran down to the shop to cut the ends off with a sharp fresh blade.  You can see that there is no unraveling at all.   This is a six strand rope.  Initially my six strand rope did unravel and it took me months to adjust my twisting and ratios before i got it just right.  I do fear that those who initially bought my larger rope may experience some unraveling,  but once you get the tension correct and the hardening correct you wont have any issues.   I have since stopped using an automated machine like the ones offered and have reverted back to using my hand held version.  The  rope is manually twisted and then hardened afterwards.  None of my rope will unravel now that I have the ratios correct.

 

 

After making thousands of feet of rope in just a few months I began to get a feel for the tension in the line.  I believe that this "feel"  can only be ascertained by making the rope by hand and getting accustomed to what the right "feel" of tension and spring I can sense while holding the end of my rope walk and the line.  I also examine the lay of the rope and have a sense for what is correct now.   I also do this when twisting the initial individual strands.  Its a matter of feeling that it is correct.

 

Last month I brought my rope walk into my club meeting and made a 21 foot length of .045 rope in about 10 minutes.  It initially started out as three strands of thread that were 26 feet long.  After twisting the individual strands...they were now just 20 feet long.  Give or take.   After twisting all three strands together the line was lightly waxed and then hardened.   This stretched the rope to 21 feet long and as soon as I finished it up...I cut the rope in half with a sharp blade to show how the rope would not unravel...

 

It is absolutely possible.

 

Chuck

 

 

[twintrow]

So Chuck when you say "hardened", you mean it is stretched after making it?

And as far as twisting the individual strands first, that isn't possible with the Byrnes or Alexey machines.  At least not as a function of the machine.

So, would have to be done off the machine first?

I also have the MS rope walk mounted on a 10' bar, and I do remember your saying to pretwist the threads about 50 turns prior to braiding.

I was hoping the electric machine with a take up reel would allow me to make much longer spans.  Doesn't take long to use up 10' rigging.

thanks

Tom

[Chuck]

Those machines do twist the initial strands separately as that is the way all rope is made.   The key is to adjust the speeds so that initial twist are the correct amount in comparison with the turning of all three strands together in the opposite direction.   I like the feel of the manual machines better because this can be adjusted to suit where as the machines make this difficult to feel and adjust.  You have to finish a whole spool before you find out that the rope has the correct opposing tensions.  

 

To harden the rope I dont do anything elaborate.  I just stretch about a 2 foot section of the rope at a time before I cut it free from the rope walk.   I stretch it for just a fraction of second.    Then I cut one end free and pull it lightly.  I dont pull too hard or I will break my machine on the other end of the ropewalk.  Just a quick light stretch.  You will "feel" when its enough.

 

In fact...if after cutting the rope free from one end of a manual machine it kinks up or it unravels....thats the sign that the tensions are not correct.  If they are correct the line will not kink up or unravel at all.   Its a pleasure to cut a length of rope free and see it just sit there without kinking or twisting.   Thats when you know the opposing tensions are perfect.

[popeye2sea]

Morope will practically fall apart when cut because it is nylon.  Nylon rope has no "memory" or stiffness to hold the lay at all.  That is also why it is easier to splice cotton or hemp rope.  The lay of these ropes will be preserved to some extent when separating strands.

[BANYAN]

Chuck is spot on with the Byrnes ropewalk (and I therefore assume the Russian version as well).  You can pre-wind BUT the speed of the machine is the most important.  As Jim has a variable speed controller (no scale) this has to be pure judgement.  I learned the hard way to first spin the machine for a short while (no tension on the hand wheel) until the strands have wound to a 'certain' degree - this is a judgement thing also based on the number of strands and size of the stock thread.  When it looks about right apply tension to the hand wheel to causer the spools to wind the rope strands and lay the rope up.  I also harden the same way as Chuck by stretching as it comes off the spool but as I use a cotton-polyester thread it also retains some elasticity so I hang lengths of scale rope with a swivel weight at each end over night to try and remove all stretch.

 

The other factor I have found with Jims machine is to stay SLOW!  Jim suggests you can speed it up as you get practice / become more experienced; however, I find that speeding it up too much requires different pre-tensioning/winding of the threads.  I have had best results keeping the machine relatively slow - the best I could describe is that I am winding the take-up spool at about one turn every two seconds (ish).  I hope that helps.  Please note I am still only making LH lay rope and have yet to experiment with RH lay, but as with Chuck's rope, I can cut it with no parting of the strands at all.

 

cheers

 

Pat

[twintrow]

Pat I'm not clear on how you can pre-wind the thread.  Isn't it on a bobbin?   One reason I bought the machine was to make a lot of rope at one time rather than short pieces.  I fill each of the three bobbins with about 30-60 feet of thread.

thanks

Tom

[Chuck]

Tom

 

The three bobbins should spin independently to twist the three strands first.  Thats what the Byrnes ropewalk does.  You cant make rope unless the three strands are twisted first and then afterwards you twist those three strands together in the opposite direction.   Its the opposing tension that keeps rope from unraveling.   Otherwise you are not making rope.  You are just twisting three strings together and using glue or something to keep them from untwisting.   With those machines its just all done at the same time.  Without the initial twisting there is no way on the planet that the rope wouldnt unwind afterwards.  

 

I am sure those three bobbins are actually spinning independently to put the initial twist into each thread before they are laid up into rope.  Its the only way you can make rope.   As far as I  know anyway.

 

Chuck

[BANYAN]

Hi Tom,

 

Chuck has pretty much answered as much as I could and based on his greater experience.  My comments are based on assumptions as I have not actually derived how Jim's spools spin.  My assumption is that when you stop the winding by tension on the hand wheel, this causes the spools to engage.  As Jim states you need to use RH laid stock thread and load/configure the spools/bobbins in a set way, this implies that the spools are spinning the rope from threads against the lay of the thread which is now pre-tensioned.

 

What I meant in my statement is that I allow the basic/initial motion of the winding action to take affect to pretension the threads before I start spinning the rope.  My current 'work flow' is to start the machine at the desired speed and hold the take-up spool so that the machine pretensions the threads and starts to wind the slack to the point I feel resistance on the wound threads pulling on the take-up spool.  At that point I tension the hand wheel and hold it to engage the spools. This seems to create a reasonable rope as you have the counter tensions of the stock thread and the made-up scale rope working against each other to keep the rope 'tight' or in suspension/balanced.

 

I hope this clarifies my comment?

 

cheers

 

Pat

Edited January 1, 2014 by BANYAN