First, thank you Tim and Michael for your kind words.
Second, that "knock knock" noise came from the metal pieces within the core because the metal pieces don't fit the inside wall of the core perfectly. However, these pieces do not move along the length of the blade within the core, because if they do, they will shift the balance point in action.
The upside are that these slight unfitness allows them to travel through the curved cores and a hit is always audible even in video where the camera was quite a distance away.
The downside are that it's noisy and the very slight rattles may get into the nerves of some practitioners.
Because of the reasons above, I've eliminated these noises in the new RSW I've made by fitting the metal pieces with the core better. The noise and slight rattling are gone. However, I've yet to test it in hitting someone and see whether the hit will still be audible in the camera. I dun think it's a very important feature though. The realistic handling characteristic always comes first!
I've also modified the construction of the metal pommel in the new ones to make them sturdier and longer lasting.
p.s. I injured myself during a solo drills under rain on 20th this month and I'm now literally disabled. My left butt joint causes me so much pain that I can't sleep well. I've visited doctors and received treatments but still with no effect. <img src="/forum/images/icons/frown.gif" alt="" /> Whadda way to start a year (a chinese new year).
