Double grinner or uni knot

FlyForumAdmin

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Double grinner or uni knot


Use: Joining two lengths of leader material

Description: This is an excellent knot for joining two lengths of nylon because the two halves of the knot are tightened independently.

Tying:

1. Overlap the two lines to be joined by 150mm.

dgrinner1_m.jpeg




2. Take one end and form a loop that over-lies both lines. Pass the end around the two lines six times. Pull the end tight and form the first knot.

dgrinner2_m.jpeg




3. Now repeat the process using the end of the other line.

dgrinner3_m.jpeg




4. Pull both lines to slide the two knots together and trim the tag ends.

dgrinner4_m.jpeg


dgrinner5_m.jpeg






Graphics of knots drawn by Tim Pegg of Thilmcraft Graphics. E-mail: thilm@paston.co.uk
 

Mostyn

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A double nail knot-but without the use of a nail. There are easier knots to achieve the same kind on join.
 

lhomme

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Yes Mostyn,
but it's (IMO) the only reliable knot to link two (thin) fluorocarbon lengths together and make a dropper in the mean time : don't cut off the excess lengths but thread them crosswise through the gap before you slide the two knots together. Cut of the weakest link and you're left with a reliable dropper in a 90° angle on a fluorocarbon point. Never has let me down.

Johan
 

mancfly

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Yes Mostyn,
but it's (IMO) the only reliable knot to link two (thin) fluorocarbon lengths together and make a dropper in the mean time : don't cut off the excess lengths but thread them crosswise through the gap before you slide the two knots together. Cut of the weakest link and you're left with a reliable dropper in a 90° angle on a fluorocarbon point. Never has let me down.

Johan

Totally agree Johan! I have been using that dropper method for over a year, and it's the best! I came up with the idea independently, and posted it on a thread in here several months ago. If it already existed, i have never seen it elsewhere.

I ponder a lot about knots, droppers and how to ensure tippets to dry flies are submerged. So far, so good, it's a journey! I always question the norm if i am not satisfied with it.
 

dtj

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Apr 12, 2013
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There is an article in the latest trout fisherman which suggest the original use of uni knots only had 2 turns and any more than that weakens the knot. I must admit I've only been brave enough to go down to 3 turns which seems to be ok.
The uni knot i use is just one half of the double grinner. Has any one else tried it with less turns do you know.
 

wishiwasfishin

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I have started using a 2 turn grinner, and have been really pleased. No pigtails, draws down easily and securely, and most importantly, no breakoffs at the knots. Have used it primarily for attaching flies. Highly recommended!
 

3lbgrayling

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Totally agree Johan! I have been using that dropper method for over a year, and it's the best! I came up with the idea independently, and posted it on a thread in here several months ago. If it already existed, i have never seen it elsewhere.

Old as the hills.;)

Jim
 

mot

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Just a word of caution on the number of turns. High diameter fluoro will take a 2 turn uni knot quite happily. With lower diameters or with other materials I have found that they are prone to slipping on occasion. So with lower diameter fluoro I use 3 turns and with co-poly I use up to 5 for the thinner diameters.
 

jada0406

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Hi',
Another advantage of the double-grinner that I found and used sometimes when salmon fishing in summer, usually, was that I could pull the two single grinners apart, and tie in a dropper if required. The dropper length was passed through the slot created by opening up the knot, then a grinner knot was made passing the new material around the upper length of the leader. The new single grinner knot was then ''snugged down'', and the moistened double-grinner was closed on the dropper length, which stood out at right angles to the leader. This allowed the tying of a light dropper into the heavier main body length of the leader. My old salmon tutor wasn't happy with me fishing droppers for low water salmon fishing, until he saw me catch a few fish on the skinny size 10 Stoat's Tail, Stinchar Stoat or Thunder Stoat that I used as a dropper most often. If he had seen how the dropper was sometimes tied in, he'd have had a fit!! But, I never had a dropper break when playing a fish, or when I had a fish on the bigger fly on the point. Cheers, jadaTC
 

jonesa100

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Also good in the single form for a loop know to allow more fly movement, also for plugs instead of a rapala knot. Will tighten down when a fish takes.
 

johnclayton

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The grinner knot and the uni knot are different knots the grinner has six turns up the line then a loop is formed and six turns back up, although four turns each way with modern nylons is fine.
One of the problems is that most fishing books get it wrong and so it continues, although if you look on Youtube the correct grinner is shown.
Having said that the uni is an excellent knot and is actually a variation with less turns of a hangman's noose and has been known as the gallows knot in the past and some forty or so years ago was renamed the Duncan's loop.
The Grinner was invented by Dick walker in I think the 1950's and was named after his grandson whose nickname was 'Grinner'.

Johnclayton
 

nedun

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Oct 13, 2010
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Correct Duncan Loop:
There are many web-sites that describe and illustrate a fishing knot that is variously known as a Duncan Loop, Uni-Knot or Grinner.
In Geoff Wilson's “Complete Book of Fishing Knots & Rigs” the illustration of the “Duncan Loop” is shown improperly since the initial loop is formed on the standing line side of the hook eye.
This improper illustration of the Duncan loop is a non-slip loop that does not have similar strength as the Duncan loop and to my knowledge has no name.
When the initial loop is formed in the tag end portion of the line after passing through the hook eye it can form a proper Duncan Loop.
The illustration immediately below labeled “Uni-Knot” is a proper illustration of the Duncan Loop although the snugging and final setting are not shown. The Uni-Knot is a later renamed copy of the original Duncan Loop.
If pulled down and set properly the final configuration of the Duncan Loop, Uni-Knot or Grinner are all the same.

I believe that some of the confusion lies in the manner of which these knots are pulled down after the last wrap with the tag end is passed through the initial loop. In my knot and the Uni the tag end is pulled in the same direction as the standing line with sufficient force to allow the wraps to wind back over themselves to form a neat spiral over the standing and tag lines like a nail knot tied back over on the line itself. If this is not done the knot will not fold over and therefore form knots that differ in their final configuration and strength.
 

speytime

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I agree with mot... higher diameter can take less turns, I always use three on heavier and 4 turns on lighter nylon.
Tied like the illustration I leave the forward facing tag end as my dropper.
If you use the hook to draw the knot up it will give you a pig tail.
Pull the knot tight away from the hook using the tag end then slide the knot down to the eye and give it its final tighten and it won't pigtail.

Al
 

Mithertap

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Dec 16, 2020
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Yes Mostyn,
but it's (IMO) the only reliable knot to link two (thin) fluorocarbon lengths together and make a dropper in the mean time : don't cut off the excess lengths but thread them crosswise through the gap before you slide the two knots together. Cut of the weakest link and you're left with a reliable dropper in a 90° angle on a fluorocarbon point. Never has let me down.

Johan
 

Mithertap

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Hi Folks , new member here returning to fishing after more than 20 years away , and just having a good read , how things have advanced in all this time, I mentioned to a young lad that it was the grinner knot that was my preferred knot ,once shown he called it the uni knot , so it appears it’s now known as that , I saw reference to the Duncan Knot above , In my day the Duncan knot when tied had the loop formed in the main line and the grinner now called uni knot ? has the loop in the tag end so this has always been my understanding and how it was taught to me so many years ago,

Ps I also created my droppers by passing the ends through the gap when joining my leader / Tippet shown to me by my grandfather who was shown by his father , so as one lad said as old as the hills but a great method ,
Just like to say enjoying reading the posts on the Forum Regards
 
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