A miller's knot, also known as a sack knot or bag knot, was originally used by grain and flour millers to secure the bags containing their goods. It is a strong, secure and stable knot that can be used for tying up the neck of a bag, tying two objects to each other or temporarily binding the ends of a rope. Despite its ancient origins, this knot is still very useful.
Things You'll Need
Hold the neck of the sack in one hand. Pass the rope behind the neck of the sack so that both ends are facing you.
Hold the left end of the rope in one hand and wrap the right end of the rope around the bag, so that it crosses over the front and around the back. You should end up with both ends facing you again.
Repeat Step 2.
Loosen the wrapped rope around the neck of the bag so that two fingers fit underneath the rope.
Tuck the right end of the rope under the wrapped rope and pull both ends to tighten.