Dry your Nunchaku after use and before storage in a cool dry environment, check connections and replace when required. These days you can purchase replacement bearing kits or you could convert these to cord. You can use mountain climbing cord of your choice to replace the frayed cord types. However I would tend to strengthen the connections by using three or four cords instead of two, where the cord diameter is thin or more likely to wear. With a recent purchase of some custom hand made Nunchaku, I have used 6 mm cord looped and knotted twice in the center of the connection. The knots are quite large and need to be dressed so that they interlock and present neatly before tightening and finishing the ends.
Nunchaku Swivel repair kit
An alternative to cord for the Lighter foam Nunchaku is to use a quite stiff 1-2 inch wide Nylon Ribbon, using a two strand connection with a counter twist in each strand. There are two reasons why I like this set up, one is that the nylon ribbon seems to shirk of fraying in the lighter foam Nunchaku, this appears to be aided by the twists. Secondly these counter twists appear to also allow the Nunchaku to spin more readily during the swing. I have only had one piece of ribbon to try with the light foam type. Whether this effect will be seen when this set up is applied to a heavier wood corded type is yet to be discovered. The strength of the ribbon will be important so the thicker and wider the better, but the stain imparted in use has snapped half inch ribbon, I am still trying to source some wider ribbon for trial on the wooden Nunchaku. Nunchaku cord repair kit.
When inspecting Nunchaku check for breaks in the plastic cores of the foam types by gentle flexing, check for frays and soften exposed plastic ends internally where the surface meets the cord with a light grade sand paper. Wood Corded Nunchaku, check for frays, you can sand paper the area that meets the cord if rough and lubricate with wax or a little olive oil, check shaft for splinters or breaks.
Its important to get your knots right, even on the light Nunchaku, as these still fly away at some speed. With safety in mind some study on this subject would help. I will try to get some pictures of some knots that can be used for the different set ups and for the set ups I use. The following three images show the knot used for the double knot in the center of the connector/bridge. The first is expanded to show the routes of the cords.
The next two show the knot tightened and dressed, you really have to tighten these down, and melt a large head on to each end and a finally tighten again, check knots regularly during and before training.
From above and below.
See this knot on youtube here at the freestyle forum where trojanman has kindly made a video.
With 6 mm cord used on my custom made Nunchaku, the combined knot is quite large. However, this may be useful in the application of locks and blocks to limbs etc.
Other useful tips on knots
Now where were we...ahh
Accidents will happen.
If breaks to the sticks occur and are near the halfway mark with any of the types of Nunchaku convert to a whole and half set by cutting down and sanding broken edges to a smooth finish. Using this set of Nunchaku (SO-SETSU-KON) opens another avenue for appraisal of your techniques. Generally you should not be hitting objects in such a way or with such force that you damage the type of Nunchaku that you are using. You should also be training in an area adequate for those techniques that you wish to perform.
Dont forget the third dimension, that of height.........
Make sure you are not standing just under strip lighting or other similar hazards. Oh, and do not forget to check behind you and be aware of small children and pets, if possible train away from any such distractions or likely dangers.
Do not leave the plastic types on the floor as they will break readily when trodden on, the other round or octagonal solid types may well cause someone to trip if they are trodden on, so store your Nunchaku away when not in use.
Make your training as safe and as productive as you can.