Bokken, Jo and Martial Art Staff Maintenance
Maintain your bokken, jo or martial art staff when necessary according to the following guidelines:
1) After several months of use, your bokken, jo or bo staff may need maintenance. If the surface looks dry or faded, as if the oil finish has worn, use Kingfisher Finish Oil type M. This will protect the wood from atmospheric humidity swings as well as wear from handling. Don't overdo it! Finish oil treatments aren't needed if the original finish is still in good shape! Use very thin coats. Avoid a heavy build up of oil.
Contact in Paired Practice
Due to its unique cellular structure, Appalachian hickory is the toughest and most resilient material available for wooden martial art practice equipment. While most martial artists using wooden swords and staffs do not engage in abusively heavy impact training (and hikers using the Kingfisher Hiking Stick would rarely engage in continual impact exercises), there are two considerations for those of you engaged in paired practice - shock strength and dent resistance. In most materials, extreme hardness is associated with brittleness. Hickory, while amongst the hardest domestic American woods, is not as hard as some tropical woods. It has, however, a much higher shock strength than practically any wood and so it is not surprising that some harder species, with higher density and hardness, would superficially appear to be stronger but actually have a much lower overall shock strength. The advantage of a very hard (but brittle) weapon would be its resistance to denting but the drawback is its lower shock strength.
The key consideration when comparing Appalachian Hickory with tropical and exotic woods, including Japanese White Oak, (which gets brittle over time) is that there is nothing that can improve the shock strength of a hard but brittle weapon but there is a procedure to increase the surface hardness of an incredibly tough wood like Appalachian Hickory by using a tempering or work hardening method during the early life of the weapon - a kind of "break in" period. This is known as "Running in ".
Method of "Running in a New Weapon"
Preparing a bokken or jo for heavy impact takes some time, patience and control. Consider the surface of the wood: If the weapon is used too aggressively at first - especially against very hard materials - there is potential for more noticeable denting, grain raise and splintering at the perimeter of the dent crater. On the other hand, if it is subjected to slowly increasing impact energies, the surface becomes progressively compressed and hardened with continuous striking. Rather than deep conspicuous dents in isolated areas, the wood will have an overall patina of even compaction noticeable only upon close inspection. The weapon will develop a hard surface with a flexible tough core. This is the condition to be sought and often the weapons of experienced practitioners will achieve this state naturally.
All wood can be damaged if hit hard enough. This is especially true of weapons that have not been broken in properly. Your Kingfisher sword or staff, made of Appalachian Hickory is unlikely to fail in any case, but the user is cautioned to exercise good judgment and replace the weapon if obvious damage is evident.
2) Warp: all wood is subject to internal stresses. This is caused by atmospheric moisture changes. Kingfisher Appalachian Hickory (and no other kind of wood) can be easily adjusted for straightness. This may be necessary for seasonal changes in your area or items shipped to differing climactic zones.
Consider that the wood has absorbed atmospheric moisture and the swelling or shrinking of fibers has caused an internal stress at the cellular level. By over-bending in the opposite direction of the warp, the stresses will be relieved.
First, sight down the wooden sword or staff for straightness
A tree branch structure is is handy for leverage
With a thinner staff, it's often possible to straighten the wood by hand alone as shown above, however, this may take quite a bit of strength.
Above, Benny straightens a thick Iwama bokken. We use the shop vise with softwood blocks to protect the surfaces. Notice in all of these photos that the wood is over-bent in the opposite direction of the warp. At first, try a bend, sight the weapon for straightness and repeat if necessary. If you've bent too much, simply bend it back.
If you have any trouble, send the bokken or jo back to us and we'll fix or replace the item if it can't be adjusted.