Locking Brummel Continuous Loop Tutorial

[PrisonerOfGravity]

There is information on HF about making continuous loops using the bury method (Opie's tutorial is a great one). These look clean, and with an adequate bury length, they are super strong, theoretically retaining nearly 100% of rope rated strength (x2 for symmetric loop). I trust these with my weight.

That being said, to resist creep under light or cyclic loads, or just for peace of mind (ie the same reason a locking brummel splice is often used instead of a bury splice), I like to lock the loop before the bury. I have yet to see a method of making a truly locking continuous loop either on HF or anywhere on the internet (please point it out if I have missed it), so here it is my method. The only catch is that it turns out as a figure 8, which makes it slightly less clean looking as the bury only loops, but works in the same applications.

[PrisonerOfGravity]

Continued...

[PrisonerOfGravity]

Because one part of the completed loop passes through the other, you can easily manipulate the loops so one becomes larger and the other shrinks. You can see this in the pics above, where I have taken advantage of this to temporarily get longer straight sections in which to do the buries (my fid can't handle curves). If you enlarge one loop to the extreme, the shrinking loop will invert (the 8 will become an 0), leaving you with an unlocked but otherwise intact bury loop. The only way I can see this inversion happening in use is if you connect everything to one loop of the 8 and nothing to the other, and who would do that? If you haven't cheated on your bury lengths, the inverted version should be equally strong, you will only have lost the benefits of the lock, be they real or imagined.

[Bubba]

Excellent pictures but I'm having a hard time understanding why it needs to be a figure 8? I'll have to examine the pictures on my laptop later. My Blackberry is too small to look at them.

EDIT: ok, I closed my eyes and visualized it and now I think I understand. The part going through the loop that creates the figure 8 is keeping the two splices in place and aligned so even if the bury was unloaded, the buried amsteel can't go anywhere.

[OneThing]

Excellent! Another item goes on the list to make. Very good tutorial with the pictures as well.

[dragon360]

What was the starting length of the amsteel used?

[PrisonerOfGravity]

Bubba, the '8' shape is just a side effect of building in the lock. I have yet to find or dream up a way to build in the lock and end up with a '0' instead of an '8' shape. If such a thing exists, it would be my preference.

[Tijereyes]

Bubba, the '8' shape is just a side effect of building in the lock. I have yet to find or dream up a way to build in the lock and end up with a '0' instead of an '8' shape. If such a thing exists, it would be my preference.

We need to hire someone who knows the topology of knots.. I imagine it's theoretically possible, but only if you have one those fancy materials that can go through itself (like a Klein bottle)

[PrisonerOfGravity]

dragon360,

For that 9" loop in 1/8" Amsteel I used 41.5". I wanted to make the smallest loop I could while using the full bury lengths recommended by Samson.

-Bury is 72 x nominal diameter, so 9" for 1/8" rope. Should have added 1" to each end for tapering but ended up tapering into the 9".
-Outer layer of Amsteel shortens by about 20% when there's a bury in it, so to hide the 18" worth of bury, we'll need 18"/(1-0.2)=22.5" of rope.
-rope total, 9" + 9" + 22.5" = 40.5"

[PrisonerOfGravity]

The part going through the loop that creates the figure 8 is keeping the two splices in place and aligned so even if the bury was unloaded, the buried amsteel can't go anywhere.

If I understand you correctly, this is not the case. The strand that passes through the centre of the brummel lock is simply passing through and does not contribute to the lock or the integrity of the loop in any way. The strength comes from a locked brummel (if my terminology is correct) between the two strands that the buries go into.

In otherwords, you could cut the strand that passes through the other (where they cross), and you would end up with a specimen of an end-to-end locked brummel splice, albeit between two very short ropes.