martial arts - kenjutsu - how to make a bokken.doc

8/10/2019 Martial Arts - Kenjutsu - How To Make A Bokken.doc

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How to make a bokken

Wood selection: You must balance weight, strength and crush resistance according to what you are going to use thwood for. Price, especially if you are making your own is not as crucial since you will pay more for a cheap"maple" bokuto from Taiwan than you would for that much ceylon ebony.

Weight is crucial especially for the Aikido types who tend to go up against sensei not haing the faintest idea wha

he is going to do. !f your bokuto #$ %oken... #$ #$ %okken& is slower than his due to massie weight& you

often get clunked. ! make sure my boken is lighter than sensei's if ! can manage it. (ifting him with a heay oneusually works&.

)trength is related to the "absolute" strength of your wood, and to the "relatie" strength of your bokuto compared

to your partner's. A good %ra*illan %lackwood bokuto will simply destroy a red oak bokuto within about three hit

+rush resistance is the ability of the wood to dent without the fibres breaking causing splintering.

You also need to worry about the grain pattern of the wood. o knots, and a smooth grain that doesn't run out half

way down the blade. The grain must run down the blade obious& and also be lined up so that it runs from back to

edge not so obious&. T-!) /A) T-AT %0#+$!( W!T- %#$1T# )-#102 %/ 2#/ W!T- T-/

/2(/ not the shinogi as is being suggested in some of the mail here. There are some thoughts on blocking likethis from some senior 3apanese sensei as well, !'ll try to find the releent item in the newsletter and post it soon&.

This is the reason ironwood is usually not good for bokuto, the grain usually goes all oer hell and you're sure to

get some that go the wrong way about 456 way down the blade.

orth American -ardwoods:

-ard aple: (ood crush resistance, tight grain, good strength and weight for eeryday practice.

White #ak: #ften poor crush resistance due to porous grain, if a tight grained piece can be found, will often make

an e7cellent bokuto. 8ed #ak, Pin #ak etc. are #T suitable.

-ickory: y faourite, it often shows heartwood and outerwood of two different colours, one harder than the othe-ickory is slightly "shaggy" and so must be sanded fairly often. /7cellent crush resistance and strength with fairly

low weight. Probably the best all round orth American wood for weapons.

White Ash: 1sually a bit light, but strong. #pen pores make it "crushable" like oak. A tight grained piece makes a

good weapon for smaller students who can't safely use heaier bokuto.

!'e used other woods such as cherry, elm, beach etc. but the suitability generally depends on the piece of woodmore than the species.

/7otic Woods

-ere are some of the woods !'e used for bokuto.


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Purpleheart: 2eep red colour, nice straight grain, a little bit crushable but can be an e7cellent eeryday bokuto if

you want more weight.

/bony, akassar: 9airly strong, black with brown stripes, more suited for lone practice suburi& than partner

practice. oderately heay. /bony, +eylon: %lack, /8Y e7pensie and hard to find in suitable grain patterns as

if you could see the grain in some pieces& !'e seen these bokuto literally e7plode on contact due to stress cracks

inside the wood. ot recommended for use in partner practice.

%ra*ilian %lackheart redheart&: Was being imported as an ebony substitute, but not any longer. !t would not glue tanything due to the resins in it, and it had a bad habit of dulling tools. This is the strongest wood !'e eer seen, !

weigh 6;< pounds, my Tachi 1chi no $urai !aido partner practice& weighs at least that much, and we use a pair othese to demonstate. )ome of the kata re=uire full stop blocks against a full strength strike. These things don't een

dent. !nterestingly, ! once accidentially sliced a piece off one of them with my "dull" aluminum iaito.

!pe: Another ery hard wood. This one is a lighter brown that, with a good finish, shows rainbow coloured flecks

that make it look like you are actually seeing into the wood. ot as heay as blackheart not much is&. The sandindust from this wood is green and turns blood red when you wash with soap. A small note here, there is such a thin

as carpenter's cancer nasal cancer& and these e7otics with their resins are great for it. )ome of these woods can

cause an almost instant irritation so be careful.

+ocobolo: 2eep red with black stripes and swirls. (rain tends to be screwy but it is so tight it doesn't matter.-eay. Tools must be ery sharp as the resins in this can literally bounce a spokeshae off of itself.

$ingwood: ery pretty, more for looks than for partners. /7pensie.

>iricote and %okote: These are rosewoods, brown an black grain, the *iricote tends to be blacker and harder. !t als

produces a ery irritating dust, ! prefer working with bokote. ainly for show but will stand light partner work.

-eay if used against anything bought in the local martial arts store&.

0ignum itae: The hardest wood around. 0 is used in steamships as a bearing for the propeller shaft, not steel ba

bearings but ?ust a chunk of this stuff. !'e neer found a piece big enough to make a bokuto out of. ade a shoto

though, een with a crack it would pound anything else to pieces. )lightly greenish wood.

Tulipwood: ot the orth American wood that is like is@& Poplar but the stuff that some company in /nglandmade sports car frames out of. /7pensie, and hard to find a good piece. !'e made a few canes out of this wood

which is red and cream striped. (ood properties.

!'e probably tried a few more woods but can't remember them right now, if anyone wants to try another let me

know and !'ll tell you if !'e tried it.

9or a first try !'d recommend maple. !t's a nice wood to work and can be found easily. -ickory is a bit more

difficult to find since it isn't really a woodworker's wood. ore a tool maker's wood ie a7 handles etc.& Poplar is

showing up in some of the softwood lumberyards around here, it's a bit soft. !f you're wondering about a new

wood, try the thumbnail, rip and bend test. )ounds painful@ 0et go of your thumbnail then.& 4. Press yourthumbnail into the wood at a corner, does it crush easily. 6. Take a loose slier at the end and rip it down, is it a

long fibre or a short one@ 2oes the fibre break easily is it brittle& or does it bend@ ;. Take a board and put one end

on the floor, hold the other end. 0ook around and make sure nobody's in sight. ow lean on the board, if you hearit start to crack it's probably not ery strong. !f the wood passes all those tests, find a piece with good grain and

start cutting.


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About long fibres, ! once made a bokuto out of a wood called 8amin. !t had ery long, strong straight fibres and

seemed to hae good crush resistance. The first time the student used it the damn thing split right down the longa7is. ! swear that wood has absolutely no cross connections at all. 2on't use 8amin.

Parts of the bokuto

-ere is a list of parts on the bokuto, they are the same as the names for the parts of a lie blade.

$issaki: the tip.une: the back of the blade.

onouchi: the cutting portion of the edge, the 45; closest to the kissaki.+huo: the middle third of the blade.

Tsuba moto: the third of the blade closest the handle.

Tsuba: the guard, not present on most Aikido bokuto.

Tsuka: the handle.)hinogi: the ridge between the mune and the edge.

)hinogi?i: the flat plane between the mune and the shinogi

3igane: the flat plane between the shinogi and the temper line edge&.-a: the edge

Tsuka gashira: strictly the pommel fitting, butt end of the bokuto.

Obtaining a bokuto

The wooden sword is usually made from oak, maple or hickory if it is to be used in partner practice. These woods

hae a high degree of strength and impact resistance. aple and hickory are especially resistant to the splintering

which may occur after repeated denting of the blade in the contact with another weapon. #ther, more e7otic woodsuch as ebony, cocobolo or blackheart are sometimes used for their density, the greater weight more closely

matching the metal katana. These woods are e7pensie and often contain flaws which make them less suitable to

use in partner practice but ideal for indiidual training. While the weight of the bokuto may approach that of akatana, the balance is always different. The katana, due to its metal blade and wooden handle, has a balance point

much further forward than that of a bokuto.

)pecially shaped wooden swords called suburito are used to practice the indiidual cuts of a sword school. These

weapons are designed to appro7imate the balance of a katana but are much different in shape and si*e. #ftensuburito of great weight are used to strengthen the arms and improe the posture.

#nce a student has decided to study the bokuto the selection of a good weapon is of great importance. The

suitability of a sword will determine to a large e7tent the ease with which a swordsman completes his practice. A

student will own a bokuto for many years if it is chosen carefully and one should look for seeral characteristicswhen buying the weapon.

The shape and colour of the sword should be pleasing to the eye, the grip should feel smooth and free of stickineswhich will cause blisters. The grip should also be large enough in the hand so that the fingers don't touch the palm

A badly si*ed handle can cause e7cessie cramping in the hands and a poor pattern of callous formation on thepalm. The wood grain should be straight, with no knots and run from the handle to the tip. The growth rings shoul

also run from the top of the sword to the edge. This pattern will gie the strongest %okuto possible. 0ook for a

tight, closed grain which will resist denting. o warps or cracks should be seen. The wood should only be finishedwith tung oil or boiled linseed oil. -ard surface finishes such as arnish will cause the handle to be sticky. The

weight of a %okuto should be such as to allow the completion of a two hour practice which might include seeral

thousand cuts. 9or this reason, students should consider beginning with a lighter sword and then moing to a


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heaier ersion when the arm and shoulder strength permits. A sword that is too heay can cause muscle strain, an

the slowness with which it must be moed can cause problems during partner practice.

Making a bokuto

With a few basic tools it is not hard to make a bokuto. The first consideration is which wood to use. The choice wi

depend on what style of sword is being made and whether or not it is to be used for partner practice. #nce a sourcof suitable wood is found the actual piece must be chosen. 1se a board that is about one inch thick and at least two

inches wide for a bokuto. A suburito may re=uire other dimensions. The grain must be straight and preferrablyrunning along the wide dimension of the end of the board, rather than across it.

!'m going to describe how to use a lot of power tools to make your bokuto, you don't need all of these, so ad?ust th

instructions according to what you hae.

uch of the wood aailable these days is not fully dry. !f it is practical, buy your wood and store it for seeral

months to a year in conditions similar to your practice place. This will ensure that the wood is at a proper humiditleel and any faults that are going to deelop will do so before you start working.

The easiest way of laying out a pattern for the cure is to use a bokuto you hae already decided you like. !f you

don't hae a pattern then cut the board to about B4 inches long and at least two inches wide. +heck the grainpatterns and decide which end of the board is weakest, this is your handle. !f the grain has a cure then the cure othe sword will follow it. 2ecide how far along the blade the bottom of the cure will be. 9or %i*en style blades the

point of ma7imum cure is close to the handle, for other styles it is closer to the middle of the blade. ark out a

cure so that the bokuto is about one inch tall from ha to mune&. The top of the handle and the point will touch onside of the board. The point of ma7imum cure on the edge touches the other side if the board is 6" wide. +ut out

this sword blank with a band saw or a sabre saw. ! een used a C 45B inch circular saw for a few blades when ! had

nothing else. The small blade will make this cure.

This is the time to decide what tip shape you desire, some sword styles leae the point blunt while others use amodified point. The commercial bokuto mimic the point of the katana. !f you want a point cut the end at the angle

preferred.

!f your bokuto is going to taper toward the tip it should to look good&, and you hae access to a ?ointer, mark the

taper on the concae and cone7 sides and by using a series of longer and longer passes oer the blades, create thetaper on the sides of the blade. !f you don't hae a ?ointer you'll simply do this by hand when working on the

shaping of the blade.

To care out the shape some people prefer a wood rasp, some a plane. ! prefer a combination of a spokeshae and

)tanley )urform depending on which wood ! am using. ! hae a Workmate bench which is about the correct heighfor me to work on. )tart with the blade section and do the handle last since the s=uared handle will allow you to

keep the blade in the correct orientation while creating the long straight lines needed to produce a good looking

bokuto.

+lamp the wood so that you can cut out the back ridge. 9or this you also need to hae the blade clamped straightup and down. -old the spokeshae at the chosen angle and use long smooth strokes to cut the shoulders. A BC

degree angle will make a round looking blade while an angle more toward ertical will create a thin blade. This is

matter of taste. When you hae these shoulders cut to a straight pleasing line then you can start on the edge. Turnthe blade oer and work the cure into the bottom of the blade. A more rounded edge will create a heaier sword

with a more resistant striking surface. A sharper edge, while weaker, will hae a more pleasing shape. ake sure

while you are working that the edge is lined up with the top of the blade. +lamping the s=uared handle will helpwith this. The edge will often wander as you cut so be careful. !t is at this point that you determine the balance of

the blade by how much you taper the blade toward the tip.


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!f you want to mimic the katana point use a )urform to cut a plane in from each side at the tip. !f there is to be no

point or a modified point then use the )urform to round off the edges of the tip and the base of the handle. ow isthe time to een out any waers in the lines along the back.

+lamp the blade carefully and cut out the handle. This is an important step since the handle is what you grip and it

must agree with the cure of the blade. As a general rule the handle should be an oal shape with the long a7is of

the oal arranged so that you know where your blade edge is facing. !n other words, the top and bottom of the oamust line up with the mune and ha.

!f you hae access to a fi7ed belt sander then use two hands to smooth off the wood. Your straight lines will

become straighter at this point, and a lot of shaping can be done with a ;D grit belt. !f the sander has a large flat beyou will hae to create a padded "hump" on the bed with foam and masking tape so that the belt moes in a cure

to fit the concae mune.

!f you don't hae a sander, you must work much more carefully with the hand tools unless you like blisters on you

hands from the hand sanding. 1se seeral grits of sandpaper to smooth the wood and close the pores. After sandinapply boiled linseed oil or Tung oil to finish it. 2o not use surface finishes like arnish, urethane or danish wood

oil. These will create a sticky surface that will gie you blisters. An oil finish allows the wood to soak up the swea

on your hands while keeping the grain from lifting too much. !f you use linseed oil make sure it is boiled, raw oil

will neer dry. ! prefer tung oil.

!f the blade feels good in your hands and is the right weight, the appearance is not important. This is a tool and it

will soon be banged up so don't worry if it is not a museum piece.

The bokuto should be carried in a bag to protect it from sudden changes in temperature and humidity. The wood is

not fully sealed by the oil finish so changes in the atmosphere may cause warping or checking. eer store thebokuto for a long period without support along the length, and keep it out of the sunlight. Treat it with the proper

care and it will be useful for many years of hard serice.

martial arts - kenjutsu - how to make a bokken.doc

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