I have now made loads of fobs and bracelets from the square not sennet and also use a watchstrap made from one. After twice undoing and re-tightening the watchstrap, I have come to the conclusion that the square knot sennet is unsuitable for constant use with a heavy object attached to it as it starts to lossen.

I have also been experimenting with other knots and ideas. One that was successful for holding more paracord was a variaton of the square knot sennet. I started by tying a turks head knot (similar to the monkey fist) in the middle of a length of string. I then tied a square knot sennet from that to form a bracelet. I then tyed the loose ends together with an overhand knot to form a loop. This way the turks head acts as the button which is no longer needed and carries more cord.

The next thing I tried was a bracelet using a star knot sennet. This was very successful. Before this I had made a nice paracord fob using the crown knot sennet. After seeing the large diameter of the paracord fob I decided to experiment with thinner string that is about half the diameter and natural cordage. I just did the same as with the fob except for went on for longer. I ended it by threading the for loose ends through a button and tying them together with thread. It works well. If a synthetic string was used the ends could be melted togeth with better results.