Assist cord - why remove the internal cord?

[Brandon Khoo]

I was wondering why the conventional wisdom, when using assist cord, is to remove the internal cord? It makes it easier to tie but surely the cord is stronger leaving the internal cord inside?

[Mark Harris]

No idea why anyone would do that Brandon unless they were splicing (unlikely!) or using it as a sleeve.

If the assist is made from Kevlar which is the material I guess most folks here would use, then it is easy to tie knots.  So, like you I can't see any reason to remove the centre cord and never do that myself.

[Andrew Susani]

Is the centre cord used only for the construction of the weave? 

In fly tying we use mylar tubing which is a woven metallic tube with a plain fabric cord on the inside, which I assume is used only to assist in making the mylar tube.  It is always removed when tying with the mylar tube, but obviously the mylar is not used for strength.

[Dmitrii Novgorodtcev]

May be, it is just to have a choice?

If I want strong and firm assist line (for example, for dogtooth) I use it not removing the internal cord, just double it and tie to the hook.
If I want more flexibility in the assist line (for fishes which suck the hook in, like, I beleive, a yellow tail does) I remove the internal cord and use needle to make a spliced assist leader.

[Eric Tai]

Some people splice a loop on one end and then tie the other end to the hook. Aren't some of the owner assists done this way?

[Mark Harris]

Yep, I suspect some people do do that Eric, which I why I mentioned splicing as a possibility above. But I don't think this is at all common.

Tying assists is so easy as Kevlar just does not slip, so why go to the fiddly trouble of splicing?

As an aside, personally I like a doubled cord on my assists be they for fixing to top water lures or for jigging.  Makes the knotting even easier as there is just one (holding the assist to the hook shank) and the hook is looped back through a solid ring.  The only time I don't do that is when using a really long shanked hook like a Jobu as the assist cord would have to very long to allow the looping.

[Dmitrii Novgorodtcev]

As an aside, personally I like a doubled cord on my assists be they for fixing to top water lures or for jigging.  Makes the knotting even easier as there is just one (holding the assist to the hook shank) and the hook is looped back through a solid ring.  The only time I don't do that is when using a really long shanked hook like a Jobu as the assist cord would have to very long to allow the looping.

Mark,
You can have a very short assist cord (shorter than hook shank) even with long shanked hook like a Jobu, if you loop not around the hook, but around a solid ring!
Though I am not sure my explanation is clear (sorry. English is not my native language).