Its history originates in fly fishing and it’s named a nail knot because it was originally tied with a nail to make it easier but nowadays you can get a nail knot tool.
You can use a nail knot to join your fly line to the leader, fly line to backing, make or strengthen welded loops on your fly line, or use a double nail knot to join two pieces of line with different diameters for your leader to tippet connection.
How To Tie A Nail Knot
First off, to tie a nail knot you will need a tool to help your tying. This can be a nail, the nail knot tool or your nippers, a needle, or a small tube. And for clarity’s sake, let’s say you’re using the nail knot to connect the butt end of your leader to your fly line.
Take your fly line, leader, and your chosen tube and line them up horizontally in an overlapping position with the leader at the top, the fly line in the middle, and your tube, nail, or needle at the bottom. Grip all three of them below the tag end of your leader.
Wrap the tag end of your leader material around the fly line and tube back towards the mainline of the leader. Do a minimum of 6 turns.
Now you’ll need to guide the tag end of the leader through all the turns you have just made, which is why using a nail or tube tool makes tieing the nail knot a lot easier. Take the tag end and pass it through the tube or the gap made by the nail so it comes out the other side.
Remove the tube, wet the knot with saliva, and slowly pull the tag end of the mono until it creates smooth coils around the fly line. Now pull it tight again so the knot is strong and cut off the tag end.
Here is a free video showing you the steps.
Is a Nail knot strong?
Yes, a nail knot has great strength and provides 100% knot strength. This means if you tie nail knots with a 20 lbs mono onto your fly lines, they will break at 20 lbs.
What is a nail knot used for?
A nail knot was one of the most popular knots anglers used to attach leader or backing to fly lines as the knot is smooth and passes through the rod guides like it isn’t there.
There was a point when welded loops came in almost every fly line and nail knots are used less and less in this way but you can use them to strengthen your loop when fishing for bigger fish like GT’s that might break the loop.
You can also tie a double nail knot to join two light or heavy lines with different diameters. I always use this knot on my leaders when fishing for bigger fish as its breaking strain is great and better than a blood knot.
You can also visit full Best Fly Line here to see what’s the perfect fly line for your needs.
How To Tie A Double Nail Knot
Tying a double nail knot is much the same as tying a single one, you just repeat the process twice, once with each of the two pieces of line you’re attaching so that the wraps meet in the middle. It might sound tricky but it’s actually very simple.
How do you tie a nail knot without a tool?
It is much easier to tie these knots with a tool but you can tie them without one, I always do as I never seem to have a tool around on the water.
Follow all the same steps as laid out above except when making your turns, find a way to try to have them coil up, stay hollow and aligned, this will pay off at the end when you have to pull the tag end through.
If the wraps are all coiled, hollow, and aligned, you can pass the tag end through them with ease, with no tools required.
Want to know another knot tie? See our Needle Knot post here.
Is a Uni knot the same as a nail knot?
No, the uni knot and nail knot are two completely different knots. They might look a tad similar and both can be used to join two lines but uni has a different end to it utilizing a loop to secure it.
See our full break down of the fly fishing knots you need here.