Great question! Based on the video context provided, it seems like you're describing a common characteristic of the arbor knot. The arbor knot is designed to secure your fishing line to the spool of your reel. When tied correctly, it should hold firm when you pull on the main line, which is the line that will be spooled onto your reel.
However, it's also normal for the arbor knot to come undone if you pull on the free end (tag end). This is because the knot essentially works as a slip knot, where the main knot tightens against the spool, and the secondary overhand knot on the tag end prevents it from slipping through completely.
Here’s a quick recap on how to tie the arbor knot:
This method ensures that the line is secure on the spool when you pull on the main line. If you pull on the free end, the slip knot mechanism will allow it to loosen, which is why it may come undone.
If you have any more questions or need further clarification, feel free to ask! Happy fishing! 🎣