my locked brummel failed!

Hey guys, I tried something new the other day, with really bad results----I made a locked brummel on one end of a whoopie sling for my new bridge hammock-----to save a few inches, i made the bury end really short---like only an inch. Anyway, it looked good, and seemed secure until I laid down in the hammock---next thing I know, Im laying on the ground! i didnt get hurt, and the hammock wasnt damaged, but it could have been bad. After looking at the locked brummel, I realized that with such a short bury, the amsteel frayed/unbraided it self and unraveled the knot/splice. So the moral of the story is......dont do that! :laugh:

I am glad that you are alright! Thanks for the destructive testing, good info to know. :D

Yeah, thanks for the warning

Glad you're ok. Makes me want to check my whoopies again!

shows you how "slippery" amsteel is, my understanding is that most of a locked brummels strength is supposed to come from the lock.

Glad your ok, but thanks for the field test :D

Thanks for the heads up. Info like this makes life safer for us new guys :)

Curious - how long did it hold? Was there swaying involved?
This was brought up in an earlier thread, how much bury do you need in a whopping. Obviously 1 inch isn't enough. But is 3? 5?

makes me wonder about my whoopies

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Originally Posted by dammfast

shows you how "slippery" amsteel is, my understanding is that most of a locked brummels strength is supposed to come from the lock.

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This was my understanding too. I have even bought items from well established vendors with short buries on locked brummels. The lock fails by parting the amsteel fibres along the length of the bury, as has happened in this case. The bury has to be long enough to withstand this splitting force. It's not a traditional pulling force you would get with a straight brummel such as a continuous loop, but it's similar. I dont know whether or not a slightly shorter bury can be trusted, but for reference, my whoopies have locked brummels with 2" bury + 1" tapers. So far they have carried 200lb without problem. For the sake of an extra couple of inches, I would make them with a decent bury in future.

Glad the OP didn't have any injuries.

Atb

Mark

Glad your a-okay.... I use the 4/4 method, 4" gives me a 2" closed loop and 4" buried... nothings moving yet...rather be safe than end up on the ground...

Sounds like you made a "whoopsie" sling instead of a "whoopie" sling. :rolleyes:

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Originally Posted by dammfast

shows you how "slippery" amsteel is, my understanding is that most of a locked brummels strength is supposed to come from the lock.

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The strength of the fixed loop comes from the bury. The lockes brummel can provide a little strength but the constriction around the bury is what is needed. The primary reason for the locked brummel is to prevent the bury from coming out when the loop is not loaded. You can make a fixed loop without the locked brummel that holds just fine. People do this and then run a few stitches through the bury to prevent it from coming out when not loaded.

Manufacturer's recommendations for the fixed loop bury is somewhere around 6 inches, I can't remember exactly with 2 inches of that being a taper. I have made them shorter but I'd never go less than 4.5 inches. Not surprised that 1 inch did not hold. Glad you did not get hurt.

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Originally Posted by Roe Ring

This was my understanding too. I have even bought items from well established vendors with short buries on locked brummels. The lock fails by parting the amsteel fibres along the length of the bury, as has happened in this case. The bury has to be long enough to withstand this splitting force. It's not a traditional pulling force you would get with a straight brummel such as a continuous loop, but it's similar. I dont know whether or not a slightly shorter bury can be trusted, but for reference, my whoopies have locked brummels with 2" bury + 1" tapers. So far they have carried 200lb without problem. For the sake of an extra couple of inches, I would make them with a decent bury in future.

Glad the OP didn't have any injuries.

Atb

Mark

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The same happened to me his past weekend. I was using a continual loop that I had gotten through a buy on the for sale forum and wasn't sure how well they were made. Well the bury was too short and I hit the ground. I'm glad I don't hang very high so it was just a short fall on soft ground. :rolleyes:

Samson's recommended bury is 42 times the diameter of the cord.
7/64" = 4.59" + 2.29" taper
1/8" = 5.25" + 2.625" taper
Samson Rope claims a 90% to 100% strength with the lengths above.

I spoke with someone just last Friday who pulled a set of whoopies to failure using these specs.
Result: the rope failed (not on a splice) at the exact rating of the rope.

Since we hangers do not normally reach this maximum strength of Amsteel, many feel that the length of the buries can be shortened.

How much can they be shortened?
I bury all my suspension eyes a minimum of 4" (when using a locked brummel). I've never had a failure yet and am not interested in finding this lower limit.

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Originally Posted by chapinb

Curious - how long did it hold? Was there swaying involved?
This was brought up in an earlier thread, how much bury do you need in a whopping. Obviously 1 inch isn't enough. But is 3? 5?

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It failed in about 2 seconds. (no swaying involved) After It happened, I looked at the other sides locked brummel---it was ready to go too! To be honest, if I had followed directions, and put a proper bury on it, it would have been fine. (but, as my wife will tell you, Ive never been into that whole "following directions" scene!)

Also, from now on I'm going to bring a small piece of wire with me when I hike---so I can repair/modify my amsteel while in the woods if needed! (for those who havnt made whoopie slings, a bent over piece of wire is used as a splice tool)

I know that I have been tempted to use less amsteel on a project, especially when I see how fast my stash is dwindling, but so far I have gone ahead and done it as recommended. I always think that no matter it it is expensive, it is still only a matter of less than a dollar to make sure something works. Penny pinching doesn't work here.

I try and go min 4 inches,,better at 5 just to be safe,,never had a failure yet.

I'm always tempted to cheat a little bit on bury length, and it rarely ends happily for me when I do. Fortunately my failures have occurred at home rather than out in the field, and they have taught me a valuable (sometimes painful) lesson: as much as I would like the extra 3-5 inches, they are a small price to pay for peace of mind :D

I've always understood that "locked brummels" are there to hold the loop together, only when no load is applied. It just keeps them from falling apart when they are thrown loosely into your storage bin at home, etc.

The bury provides the strength for a loaded situation. If you skimp on the bury, you are skimping on the strength of the suspension.

I have completely abandoned locked brummels in favor a sewing a few hand stitches into the bury.

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Originally Posted by MAD777

I've always understood that "locked brummels" are there to hold the loop together, only when no load is applied. It just keeps them from falling apart when they are thrown loosely into your storage bin at home, etc.

The bury provides the strength for a loaded situation. If you skimp on the bury, you are skimping on the strength of the suspension.

I have completely abandoned locked brummels in favor a sewing a few hand stitches into the bury.

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I still do locked brummels, but I always sew 4 to 5 hand stitches just to be sure.

My burys are always at least 6 inches never had one slip

I am new to the forum but thought I might share what I found when making my slings. If you look on the Sampson website http://www.samsonrope.com/splicing-instructions.cfm
the designed bury should be 2 &1/4 fid lengths for Amsteel (12 strand) and 1 fid for Tenex (12 strand) on the locked brummel. A fid is 21 times the diameter of the rope. I have made several from 7/64 up to 1/4 Amsteel and all have held with no slippage.

Glad you weren't injured, but yeah I use a 4 inch bury in all but the first set of whoopies I've made. The first I did a 6 inch bury, and sat down very carefully because I thought there was no way such a thin line could hold me. :lol:

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Originally Posted by dammfast

shows you how "slippery" amsteel is, my understanding is that most of a locked brummels strength is supposed to come from the lock.

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This is not correct. The bury is intended to do all of the work and the lock is only there to prevent the bury from backing out under no load situations. This situation illustrates why the lock has little strength. A few stitches can be substituted for the locked brummel and the strength will be the same. Again, the stitches do not add strength, but keep the bury from slipping out when there is no load,

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Originally Posted by Bubba

The strength of the fixed loop comes from the bury. The lockes brummel can provide a little strength but the constriction around the bury is what is needed. The primary reason for the locked brummel is to prevent the bury from coming out when the loop is not loaded. You can make a fixed loop without the locked brummel that holds just fine. People do this and then run a few stitches through the bury to prevent it from coming out when not loaded.

Manufacturer's recommendations for the fixed loop bury is somewhere around 6 inches, I can't remember exactly with 2 inches of that being a taper. I have made them shorter but I'd never go less than 4.5 inches. Not surprised that 1 inch did not hold. Glad you did not get hurt.

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Actually, the brummel does provide strength. In fact, if you can keep the braid from unraveling, the brummel will support roughly 3/4 of the rating of the line.

A proper locked brummel splice requires 1 less fid length of bury than a normal stitched splice, which uses 3 fids.

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Originally Posted by gmcttr

This is not correct. The bury is intended to do all of the work and the lock is only there to prevent the bury from backing out under no load situations. This situation illustrates why the lock has little strength. A few stitches can be substituted for the locked brummel and the strength will be the same. Again, the stitches do not add strength, but keep the bury from slipping out when there is no load,

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The lock does provide strength, but due to how its constructed the braid needs to be secured from unraveling. A 1" bury is not enough constriction on the braid to keep it from unraveling.

One can test this buy inserting a knitting needle into the braid of the line say 1" from the end, and trying to pull the needle lengthwise down to the end of the line. It should pull out easily. Now insert the needle say 6" up from the end, and do the same thing. The braid itself is just as strong as the line, if you can keep it together. The splice aids the lock by not just normal constriction, but by keeping the braid from separating.

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Originally Posted by opie

Actually, the brummel does provide strength. In fact, if you can keep the braid from unraveling, the brummel will support roughly 3/4 of the rating of the line.

A proper locked brummel splice requires 1 less fid length of bury than a normal stitched splice, which uses 3 fids.

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Thanks Opie, it's good to hear some positive news on using locked brummels. I have them on my continuous loops, whoopie slings and my detachable RL.

When you say that the lock will support 3/4 of the rating of the line, does that mean that the line will snap at the lock? Or that the splice will open at 3/4 of the rating? How does that compare to a straight brummel splice, does that achieve the full line rating?

Thanks

Mark

Stevebo: I received my Amsteel from Dutch today. Because of your post I made sure that when I made the locked brummel for my Woopie slings I buried at least 6" of tail.

Sorry that you took a fall, but I'm sure your advice is saving us from falls.

Glad to be of service! (I was thinking of a second career as a crash test dummy---I seem to have a knack for it! :))

There once was a lad who was humbled
For shortening the bury on his Brummel
The inches he saved
Should have been waved
For this lad ended up on his bummel

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Originally Posted by PapaSmurf

Samson's recommended bury is 42 times the diameter of the cord.
7/64" = 4.59" + 2.29" taper
1/8" = 5.25" + 2.625" taper
Samson Rope claims a 90% to 100% strength with the lengths above.

I spoke with someone just last Friday who pulled a set of whoopies to failure using these specs.
Result: the rope failed (not on a splice) at the exact rating of the rope.

Since we hangers do not normally reach this maximum strength of Amsteel, many feel that the length of the buries can be shortened.

How much can they be shortened?
I bury all my suspension eyes a minimum of 4" (when using a locked brummel). I've never had a failure yet and am not interested in finding this lower limit.

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Thanks, when making anything with 7/64 amsteel I measure 6" for the bury, and then make the taper about 1 to 1 1/2. So my total length is the 6" with about 4 1/2" to 5" being full diameter bury. I haven't had any slippage or failure.

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Originally Posted by GrayDog

There once was a lad who was humbled
For shortening the bury on his Brummel
The inches he saved
Should have been waved
For this lad ended up on his bummel

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Ha! Fitting!

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Originally Posted by stevebo

Glad to be of service! (I was thinking of a second career as a crash test dummy---I seem to have a knack for it! :))

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In my life I've broken my right wrist, my right foot, shattered my left elbow (where I now have a metal plate, 9 screws and a prosthetic radius bone) and cracked ribs on both sides.

They say that everyone on average has 1.2 serious injuries during their life. So for all of you who have never been hurt, it's because Stevebo and I have been taking the hits for you.

You are welcome, but I hope I'm done taking it for the team. ;)

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Originally Posted by GrayDog

There once was a lad who was humbled
For shortening the bury on his Brummel
The inches he saved
Should have been waved
For this lad ended up on his bummel

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I can honestly say, no one has ever written a poem in my honor! Thank you, and I will treasure it always! (I think a copy of it will go on the wall in my workshop/gear room!) :)

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I think a copy of it will go on the wall in my workshop/gear room!

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Nah, not enough honor. I'm thinking... TATOO! :D

PapaSmurf:

Does your 4" bury also include the taper? How long is your taper and the overall bury?

Quote:

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Originally Posted by PapaSmurf

Samson's recommended bury is 42 times the diameter of the cord.
7/64" = 4.59" + 2.29" taper
1/8" = 5.25" + 2.625" taper
Samson Rope claims a 90% to 100% strength with the lengths above.

I spoke with someone just last Friday who pulled a set of whoopies to failure using these specs.
Result: the rope failed (not on a splice) at the exact rating of the rope.

Since we hangers do not normally reach this maximum strength of Amsteel, many feel that the length of the buries can be shortened.

How much can they be shortened?
I bury all my suspension eyes a minimum of 4" (when using a locked brummel). I've never had a failure yet and am not interested in finding this lower limit.

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I lock the locked brummel with a soak of superglue!

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Originally Posted by MDSH

I lock the locked brummel with a soak of superglue!

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:thumbdown: Probably just creating a point of failure.

Quote:

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Probably just creating a point of failure.

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+1

I tend to trust the manufacturer's guidelines considering the stresses this product is designed for.