Fly Fishing Knots: Nail Knot Video
The Nail knot is the cleanest way to permanently attach a leader to a fly line.
How to Tie the Nail Knot
2. About an inch from the end of the fly line, pinch the monofilament against the line. Begin winding the tag end back over itself, the fly line, and the tube, progressing toward the end of the fly line. Each turn should be tight against the preceding one. Continue to pinch with the one hand, but slide the thumb and forefinger over the wraps you just made.
3. Pass the tag end through the tube so that it passes under the turns you just made. You don't have to pass the whole thing under so long as the end of the tag end is not beyond the first wrap. You should still be pinching the 5 wraps.
4. Transfer the pinching to the other hand without letting go of the coils. Pull the tube out in a direction opposite the end of the fly line. Withdraw the tube quickly and keep pinching the 5 wraps tightly.
5. Without taking your fingers off the wraps, pull gently on the tag end until it tightens against the wraps. Switch pinching hands and pull on the standing end. Repeat until the turns are snug but not tight on the fly line. Stop pinching and make sure the coils are smooth and even. If not, work them into position with your fingernail or slip the mono off and start over.
6. Once you are satisfied with your coils, pull tightly on both ends of the monofilament. It helps to wrap the butt of the leader around your hand and hold the tag end with a pair of pliers.
7. Finally, pull on the fly line and the standing part of the leader with nearly as much force as you can with your hands. This snugs the knot completely and tests the knot before you put it into action. Trim the tag end of the fly line as close to the knot as you can.