construct-FAQ - 12/13/96

FAQ: General Bow Construction

NOTE: See also the files: archery-books-msg, C-A-handbook-art, arrows-msg, 
crossbows-msg, arrow-making-FAQ, arch-hist-FAQ, clout-shoot-FAQ.

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Subject: FAQ: General Bow Construction
Summary: This posting contains the alt.archery FAQ section containing
	 construction information on building various bows at home.
	 These bows are typically self bows and longbows.
Posting-Frequency: monthly
Last-modified: 15 April 1996


This is a section of the FAQ for alt.archery.  It is maintained by me at
the following e-mail address: bblohm@hpbs1686.boi.hp.com
Comments, flames, etc. on the FAQ are welcome and should be directed to
me. Comments on the specifics of the section can be addressed to either
me or the person responsible for this section.  If addressed to me, I
will forward them to the author of the section.  If you wish to see this
section cross-posted to another group, please e-mail me a request to do
so.  If I can access that group, then I will so cross-post whenever I
post this section.

Bill Blohm
bblohm@hpbs1686.boi.hp.com


Cross-post to rec.org.sca requested.

Please send your questions, additions or corrections to:

      Rob McNeur    Rob@ccc.govt.nz

**********************************************************************

CREDITS
      Rob McNeur    Rob@ccc.govt.nz
      dervish@ogre.demon.co.uk (Pip Sullivan)

**********************************************************************

This is not really a FAQ, more of an OAQ (Occaisonally asked questions)

------------------------------------------------------------------------
Traditional Bowmaking
=====================

This is intended to give guidelines in the construction of your own 
traditional longbow, mainly of the Self-bow style. For those interested in 
traditional composite and/or recurved bows, I recommend the Asiatic-Turkish
section of the FAQ.

(I apologise for the quality of the ascii text graphics used, but could find 
no other way to represent some of the concepts)

Self-bows are those which are made fully of wood, either a single stave, or 
a pair of shorter staves, usually jointed at the handle, giving a single 
length.

Wood types.
===========
Some of these are well suited to Self-Bows, some better suited to making 
laminations for composite bows. 

(These are all supposed to be the preferences in the Northern Hemisphere,
USA, UK, Europe etc. Some or all of these may be available, some may only 
be available in the USA)
Yew (of course), Osage Orange, Dagame (lemonwood), Elm, Ash (most of them), 
Hickory, Oak, Birch, Black Locust, Walnut, Cedar, Juniper, Mulberry, Maple, etc.
Of the Ash varieties in the US :-
strong ash = white, red, green, texas, & oregon
weaker ash = black, blue  (both may be adequate for a bow)

The main New Zealand & Australia options include
NZ - Tawa, Rewarewa (probably), Manuka/Kanuka (NZ Tea-Tree)
OZ - Osage Orange, Acaias (Wattles) (eg Blackapple, Gidgee Myal/Boree etc)
     Tasmanian Myrtle, Spotted Gum, Alpine Ash, Silver Ash

Pacific regions :- Bamboo, Lancewood (NB this is *NOT* NZ Lancewood), 
     Black Palm

Seasoning of wood
=================
The main criteria is that the wood has been seasoned (dried) fairly slowly.
If you are using commercial stuff (from a timber yard) it has probably been 
kiln-dried. This is usually OK if done properly, although can sometimes 
weaken the wood slightly if done too quickly or dried too much.
The general opinion amongst bowyers is that air-dried wood is far superior 
(Some timbers like Osage orange don't like kiln drying.) however, it is 
often difficult to acquire suitable air-dried timber without doing it 
yourself (over a long period).
Also, if you have the equipment to be picky about it, the wood should 
ideally have been dried to suit the region it is being used in. This is 
sometimes relevant if the wood is imported, kiln-dried in one place and 
used in a region with a higher or lower humidity. And if kiln-dried too much, 
(below about 10% Moisture content) this is also likely to weaken the wood. 
However, as most people don't have the equipment to test, the moisture content 
is usually just assumed to be correct.

Preparation
===========
Ideally, the wood should be split rather than sawn, preferably Bow staves 
should be radially split from a log/branch which is 4-6 inches diameter plus.
This means that it is more likely that the wood will follow the grain, whereas 
sawing is often more likely to cut across grain. The more the bow-stave 
follows the grain of the wood, the less likely it is to break, and the 
stronger it is likely to be. If the grain runs across the bowstave at any 
sort of an angle, this will weaken the bow to a certain extent, the amount of 
weakening depending on the degree of the angle of the grain.

Usually the sapwood becomes the back of the bow, particularly in the
traditional "D" section longbow.  Grain alignment is not as critical when
using LEMONWOOD/DAGAME, which is recommended for the beginner.


Ideal line of grain and wood growth rings
=========================================
(NB Variations in these are perfectly allowable, but the greater the 
variation from the ideal, the more likely it will be that the completed bow 
will be weaker and more prone to breakage in use or in construction)

cross-section
      Back
|-------------------|            ----------------------------------------------
|-------------------|  Growth     -------------------------------------------
|-------------------|  rings       ----------------------------------------
|-------------------|                              -----
|-------------------|                 (exaggeration of the grain lines  
|-------------------|                   along the side of the bow)
      front

    Back of bow
____________________  <---sapwood
\__________________/
 \________________/
  \______________/
   \____________/  
    Belly of bow  

The grain should also run straight along the length of the stave from end 
to end. If it curves up and down, then you have to alter the design to 
follow the grain. At all times, the back of the bow should follow the line 
of the grain and the front (belly) of the bow should follow the line of the 
back (with the appropriate tapering required).
Likewise if there are any knots in the wood, you have to alter the design 
to allow slightly extra wood to go around and support the weaker knot wood
(or 'pins').

eg if the grain dips down in the bowstave, then the bow should also be shaped 
to follow that curve
(from a side view of the grain)
------\     /-------------------   (here the dip in the grain will be followed
------\\---//-------------------    in the bow, resulting in a bow having a 
------\\---//-------------------    curve in one arm. If not followed, the 
------\\---//-------------------    grain will be cut, weakening at this point.
       \---/


With twisted staves, it is best to joint two "sister" split pieces from the
same log (ie two pieces split next to each other from the same log - and which
would then have similar twists) and joint them at the handle using a Z- or 
FISHTAIL SPLICE (as below).   This ensures that both limbs are complementary, 
even if badly twisted.
                    Z-Splice                  Fishtail Splice
-----------------------/-------------------------/----------------------------
                     /                         / 
                   /                         /
                 /                         /
               /                         / 
             /-------------/           /
                         /             \
                       /                 \
                     /                     \
                   /                         \
                 /                             \
---------------/---------------------------------\----------------------------

This can also be done if you are unable to find a single length of wood to 
make a complete stave. 2 half-lengths can be spliced using either of the 
above splices, such that the spliced section will be in the handle section 
of the bow and therefore covered by the handle wrapping etc.


-------------------------------------------------------------------------------
A couple of Bow designs follow.
One is for a traditional self-longbow (D-style), the other for a self-flatbow
Neither should be taken as the 'Sole' design, both are strongly modifiable 
to suit different types of wood, personal preferences, preferred weight and 
drawlength etc.
Either bow can be 'backed' with a strip of rawhide, silk, sinew, hickory etc 
to increase strength slightly but is mainly used to aid rapid return to 
straightness and also provides some protection to the back of the bow.

To work these, you will need a straight edge (or string-line), pencil, saw, 
hand rasp and/or drawknife and/or spokeshave, sandpaper. A Vice is also 
very useful, as long as the bowstave is gripped between blocks of wood etc to 
reduce damage to it.
The professionals often speed the process up with a bandsaw, but these have 
a tendancy to waste a lot of bowstaves until you know what you're doing.


Initial preparation of the back of the bow
==========================================
The back of the bow should be the side which is closest to the outside of 
the tree or branch if it can be determined (ie. sapwood - particularly for YEW).

In many bows, the back is sometimes made in the sapwood of the timber, with the 
bulk of the bow in the heavy heartwood. Whether to use the sapwood or not 
is dependant mainly on the type of timber being used. Yew's sapwood has 
properties that make it ideal to be left on as the back of the bow. With many
species, all of the sapwood is removed and the back of the bow becomes the 
first layer of hardwood found (See below for a fuller discussion on 
whitewood bows).
If the sapwood *is* being left on to form the back of the bow, it should 
be thinned down so that it only comprises up to a maximum of about 1/3 of 
the thickness of the finished bow. Most of the strength of the bow comes from 
the heartwood.
Bows can be made totally from sapwood of many tree species, but some slight 
changes need to be made in the following designs to accomodate whitewood 
bows. (See "Woods other than Yew and Osage orange" below for details)

To prepare to work the bowstave, the back of the stave should be worked down 
until the full length of the back is all within a single growth ring 
i.e there are no rings or 'feathers' showing through on the back. This means 
following the grain no matter what twisting occurs in the grain and in the 
stave.

This should be done with handtools, rather than a saw, as it is probably the 
main reason for weaknesses in a final bow. If the growth rings are cut through 
anywhere on the back of the bow, it is extremely likely that this will be the 
place the bow will snap at. Once the back is cleaned down to the same growth 
ring, the actual bow can be marked out.


Woods other than Yew and Osage orange
=====================================
    (From: sunfire@muskoka.com (Stephen & Krista Fraser)

Probably one of the most common questions I hear is "Is it okay to make a bow
from a wood other than yew or Osage orange?"

My quick answer:  Not only is it okay, in some cases it is more desirable.
Firstly, white woods do not need to be coddled in terms of the sapwood to
heartwood ratio.  With yew and Osage, bark _and_ outer wood should be removed
to produce a good quality bow.  For a beginner, this is a daunting task.
However, white woods require no special treatment.  Once dry, simply remove
the bark and the exposed wood instantly becomes the back of the bow.

Secondly, yew staves can cost $120.00 U.S. now, while most people have the
ability to go and cut down their own maple, ash, white oak, birch or hickory
tree for little or no cost.  Often, one can pull two or more staves from a
white wood tree.  I, personally, refuse to cut down a tree unless it can yield
5 bows.  Sometimes this takes a bit of looking, like maybe two hours as
opposed to the week or so it could take looking for the "perfect" yew tree -
if such a thing exists at all.

In speaking of the virtues of white wood bows, it's impossible to fully
appreciate their value without first speaking about bow design and how it can
affect performance.

If you're the impatient type, and have already made your first bow of some
common wood according to the dimensions given in this FAQ, you will probably
have found that the resulting bow has taken a massive "set" or amount of
"string-follow".  Both of these terms refer to the amount that the bow has
bent in the belly direction when unstrung.

String follow or "set" is not a big problem unless the set is extreme
(anything over 3").  Again, if you've made a white wood (common wood) bow
according to the dimensions in this FAQ, you will probably have constructed a
bow with anywhere from 6 to 10" of set.  Set robs a bow of arrow speed - a
factor that is very important in the construction of bows.

Why?  Because a higher arrow speed means that an arrow has a flatter
trajectory, thereby making it easier to aim at varying distances.
Additionally, if you're a hunter, you'll appreciate that arrow penetration
into target is important to ensure a quick, clean kill.

So how can we make a white wood bow with the same weight, arrow speed and
poundage as a premier wood bow?  Simple.  Make your white wood bow wider (in
the case of the flatbow) or longer (in the case of the longbow).

Most bowyers agree that white woods need a factor of 20 to 30% increase in
width or length to equal the cast and speed of a premier wood bow.  In the
case of a flatbow, this amount only applies to the maximum width of the bow.
In the case of a longbow, this applies to the entire length.

Although 67" is by far the most efficient length to base a bow at, such a
thing is practically impossible if making a D-Style longbow out of a white
wood.  In my experience, I have found 79 inches to be a good base point.  This
done, I don't have to adjust any other aspect or dimension of the weapon.
With white wood flatbows, I always use 2 1/8" at widest point with handle
remaining the same width and thickness as it would in a premier wood bow.

Remember that these increases apply only to the _WIDEST_ point (in terms of
flatbow) or _ENTIRE LENGTH_ in the case of a longbow.  Adjust no other
dimensions ... these changes will do the job.

As a quick review, let's look at the advantages and disadvantages of making
bows from "white woods".

Advantages:

Cheap
Easily obtainable
More choice of woods
Outside of tree becomes back of bow.  No extra work.

Disadvantages:

Requires wider of longer limbs.
Not as "prestigious" as premier woods.


When I compare my bow with those of other bowyers, I always get a quick rush.
It comes from knowing that I didn't spend a penny on my wood, that my woods
are less endangered than those of others, and that the bow itself was easier
to work.  That lets me spend more time shooting, and less time making
shavings.


Self-Flatbow
============

Top View
--------
          ------------------------------\       /-------------------------------
                                       ^ \     /
                                   1+  |  -----
                                   3/4"       7/8" wide handgrip
                                       |  -----
                                       v /     \
          ------------------------------/       \-------------------------------

          <--------------------------------67"--------------------------------->
                                        3"
                                 <-12"-><><-4">
Side View 
--------- e                      d      c b a b c    d                         e
Back      ----------------------------------------------------------------------
          ------------------------------\       /-------------------------------
Belly                                    \     /
                                          -----

(NB, the bow is drawn to 67" length, designed for a 28" draw length. If 
your draw length is longer or shorter, alter the total length by 2" for every 
1" draw length change (e.g. draw length of 26" gives a length of 63")
Handle section (c-c) remains the same, the rest (c-e) should alter in 
proportion.)
Also, the handgrip on the belly side (c-c) can either be all of one part of 
the main bow, or else can be a second length of wood glued onto the belly 
to give the necessary depth.

First, draw a line the full length of the back, directly down the middle of 
the bow, using a straight edge or string line.
Mark the middle of the length of the stave 33.5" from each end. (a)
The handgrip will be 2" (a-b) either side of this, (giving a 4" long 
handgrip b-b) and will then widen over the next 3" (b-c) to the widest part 
of the bow (c). From c-d (12") the stave remains the same width (1 & 3/4" 
total width or 7/8" either side of the centre line).
>From d-e, the bow width tapers as a straight line down to a final width of 
about 5/8" (5/16" either side of the centre line).
Once these are marked on the back, they can be cut to shape and smoothed 
with plane and sandpaper, giving the rough shape.
>From the side, the depth of the handgrip (b-b) should be about 1&5/8", tapering 
off to about 1&1/4" at (c) and then a straight taper down to about 3/4" at (e).
Once this basic shape is sawn out, the belly can be worked down to meet the 
required weight using more cautious handtools. The Belly is kept flat 
throughout it's length and the taper towards the tips kept constant.

(See 'Tillering bows' below for details on working to weight)



Self-Longbow
============

Top View
--------
          ----------------------------------------------------------------------
          ^                               ^ 
          5/8                             |
          wide                            |= 1 & 1/4" wide grip
          V                               v
          ----------------------------------------------------------------------

          <--------------------------------67"--------------------------------->
                                         <1><3">
Side View 
--------- c                              b a   b                               c
Back      ----------------------------------------------------------------------
          ----------------------------------------------------------------------
Belly

To mark the bow out, draw a line the full length of the back, directly down 
the middle of the bow, using a straight edge or string line.
Mark the middle of the length of the stave 33.5" from each end. (a)
The handgrip will be 1" from this (a-b) on the upper limb and 3" on the lower 
limb, (giving a 4" long handgrip b-b but meaning that the upper limb is 1" 
longer than the lower one). From b-b, the width should be about 1&1/4" wide 
(5/8 either side of the centre line) and from b-c should taper smoothly down 
to about 5/8" wide (5/16" either side of the centre line).

Once these are marked on the back, they can be cut to shape (cutting 
outside of the line to allow slightly extra wood) then smoothed to size with 
plane and sandpaper, giving the rough shape.
>From the side, the depth of the handgrip (b-b) should be about 1&1/4", tapering 
straight down to about 1/2" depth at (c).
Once this basic shape is sawn out, the belly can be worked down to meet the 
required weight using more cautious handtools. 
This style of bow has the centre of the belly remaining high and the sides 
and belly completely rounded.

     Back
----------------
\              / (the back remains flat, or rather slightly convex following
 \            /   the natural line of the growth rings and the sides and belly
  \          /    are supposed to be rounded into a "D" shape. Wood is shaved 
   \        /     off with rasp, spokeshave, drawknife or scraper until the
    \      /      appropriate tiller is maintained, all the time ensuring that
     ------       the slope of the taper remains constant from handle to tip.)
      Belly


(See 'Tillering bows' below for details on working to weight)




Tillering Bows
==============
Tillering is the process of working a bow down evenly to reach the required 
draw weight at the required draw length and to ensure that bow limbs are 
balanced with respect to each other and ensuring that the "arc" of the drawn 
bow is even.
The majority of the work here is simply removing wood from anywhere that is 
not bending enough, and *not* removing wood from places that bend too much. 
The final result is a bow that bends evenly throughout it's length (Usually 
except for the handle section, although in some bows, even the handle section 
bends slightly).

The initial process.
--------------------
Initially, wood is rasped evenly from the length of each limb on the bow. 
After a small amount of wood has been removed, rest the end of the limb on 
the ground, grasp the other end of the stave in one hand, grasp the centre 
of the bow and press against the bowgrip. The object is to get the limb 
starting to flex evenly. Once both limbs have started to flex about 5-6 
inches forward from the vertical, we are ready to move on to the more precise 
tillering. Initial nocks are cut 1/2" in from the end of each limb, sloping 
at a 45 degree angle from back to belly, using something like a 5/32" 
circular rasp, pocketknife or 4mm chain saw sharpening file.
With practice, floor testing the bow can be used to get to within 20-30 lb
of the desired weight, when starting it is advisable to be a bit more 
cautious. (Floor-testing is resting one end of the stave on the ground and 
grasping the handgrip and end of the upper limb. Putting pressure on the 
handgrip causes the limb resting on the floor to flex, the amount of flex 
is determined by the amount of pressure applied to the handgrip.)

Precise tillering.
-----------------
The easiest way of doing this is to have a 'Tiller stick' and a pair of 
bowstrings. The first bowstring is a very heavy and very long one so the 
bow can be strung just by slipping the long string on without flexing the 
bow. The other bowstring is used later once the bow starts to flex evenly 
to about 12" or so.

The other alternative is to have a pulley rigged up in the workshop, so the 
bow can be drawn using a pulley and rope with the bow handle clamped down to 
the floor or bench, set up so that you can hold the rope and still stand back 
far enough to compare the developing curves.

With a spring scale, this can also be used to determine the draw weight of the 
bow.

It is also useful to trace the required curves on a section of wall or 
paper such that the developing bow can be compared against it. As long as 
both curves are graphed accurately, this helps to ensure that both limbs 
match perfectly when they are completed.

Tiller Stick
---------------------------------------
                                      /
                                     /
                                    |              top of the
                                     \             tiller stick
   /|  /|  /|  /|  /|  /|   /|        \
--/ --/ --/ --/ --/ --/ ---/ -----------

The stick is made longer than you intend to draw the bow, up to 36" long 
is good, with slots cut into one side at every inch mark. The edges of 
these slots should be rounded so as to not wear the bowstring.
The centre of the bow rests in the hollow at the top of the tiller stick 
and the string is drawn down. This can be used to both show the current 
draw weight and also the current draw length.
If the base of the stick is placed on a set of kitchen scales and the 
string drawn down level to the slots, the downward pressure on the stick 
shows as the draw weight on the scales. (The string must be held just clear 
of the stick to check the draw weight).
Also, the string can be slid into any of the slots to hold the bow in a curved 
state while you stand back and look at it to check the developing curve.
It is also useful to trace the shape of the arc on the wall/floor for 
various draw lengths to check shape/flexing. This is a sensible precaution
to set up if you plan on making several different bows.

Once the first (long) bowstring is fitted, the bow is placed in the 
tiller stick and the string drawn till the bow has a small constant 
curve. From the first time the bow is bent, the curve must be gradually 
built up from a small gradual curve to the final state, flexing it slightly 
further at each stage. And once it starts bending, it should not be drawn 
to a greater weight than the intended final weight of the bow.
(In fact, it should be worked to a couple of pounds higher than intended as
it is likely to loose a couple of pounds in the final finishing).
Once the nocks of the bow are flexing about 12-14" forward from straight, the 
normal length bowstring can be fitted and used from then on for testing.

The belly of the bow should show the growth rings meeting in the middle of 
the bow as the curve develops, and these should be running steadily out to 
the tips as the constant taper develops.

As the bow is placed in the tillering stick and drawn slightly, step back 
and look at both limbs. If they are not both curving equally, mark the 
places that are not bending enough, take the bow off the stick and work it
down further. If there are areas that are bending too much, then don't 
touch these areas until those on either side are worked down so as to 
spread the curve more evenly.
Both limbs must develop the same curve, and that curve should be fairly 
constant and even from grip to nocks.
At every stage, and every time the bow is tested, check the curves of the 
limbs. Check the curve, get them even, then check the draw weight of the bow.
Then draw the bow to the current distance several times (10-15), to 
exercise the wood. This allows the wood to slowly weaken and get used to 
bending.
Once the curves are even, take the string down another notch in the 
tillering stick and repeat the procedure until the desired draw length is 
reached.

The final weight of the bow should be about 2-4 lb higher than the desired 
weight. Final finishing (sanding etc) plus initial shooting of the bow will 
cause it to drop the final 2-4 pounds so as to achieve the desired weight. 
When the bow is completed, it is usually preferable to glue a thin 
block of wood along the back of the handgrip, shaped to fit the hand better.
Once the bow is sanded, it can be sealed with a decent polyurethane or 
similiar to waterproof, seal and protect it.
Alternatively use a polymerising gun stock oil such as BIRCHWOOD CASEY
TRU-OIL.

Then fit nocks and handgrips as required. If desired, a backing strip can 
also be added before the handgrip block is glued in place. The backing 
strip is likely to raise the draw-weight by a small amount (2-5 pounds).

NB, Once the bow has reached it's desired draw weight, it should *NEVER* be 
drawn to any greater draw length. To do so, greatly risks snapping the bow.
So don't lend it to another archer without carefully supervising them.
-------------------------------------------------------------------------------
Fitting final Nocks
===================
Final nocks can be cut 1/2" in from the end of each limb, sloping at a 
45-degree angle from back to belly, using something like a 5/32" circular 
rasp, pocketknife or 4mm chain saw sharpening file. Care must be taken to 
keep the back of the bow as clean as possible, ie it should not be cut or 
worked at all when fitting the nocks. To do so is likely to cut the growth 
rings, weakening the limb.

As an alternative, many longbows are fitted with antler or horn nocks, 
slid over the end of each limb and glued in place. This helps protect the 
wood from abrasion from the bowstring and is also quite decorative.
To make these, take a section of antler or horn of up to 4" long and 
1/2"-3/4" across at the base. The end of the limb should be shaped into 
a cone shape for about the end 1/2" of wood, and the base of the antler nock 
drilled out to fit. File or cut nocks into the antler, then spread a strong 
waterproof woodworking glue onto the end of the limb and slide the shaped 
antler nocks on, holding them firmly in position until the glue has set.

Also, as another alternative to cut nocks, it is possible to tightly wrap sinew 
(or cord) around the nocking points of the bow and glue it in place. The 
string is then slid over the ends and held in place by the loop of sinew.

-------------------------------------------------------------------------------
Optional Extras
===============
The completed bow can have the handgrip wrapped in leather, cord or similiar 
if desired. An arrow shelf (or rest) of wood or leather can also be mounted 
on the side of the grip. Often a leather, bone or shell arrow plate can be 
let into the handle or glued to the outside surface of the grip to protect 
the wood from the arrows sliding past.
The Arrow Shelf (= arrow rest) is a small triangular ledge of any material 
that the arrow rests on while drawing and firing. Some archers allow the 
arrow to rest on the top of their forefinger, some prefer the rest.

-------------------------------------------------------------------------------
Recurving
=========
Recurving will usually significantly increase the poundage of the bow, 
without needing a greater drawlength. Recurving is bending the tips of the 
limb (or the whole limb) backwards in a curve. If this is done while the 
wood is wet or hot, the wood will retain the curve when relaxed, thus making 
the bow flex more when drawn.

Recurves can be added to a bow by a variety of methods.
One method is to glue extra lengths of wood onto the tips of the bow at an 
angle to the original stave.
                             ___
e.g.                        /  /   (Gluing this extra addition on gives an
Back of the bow limb       )  (     instant recurve effect, giving a slightly
--------------------------/  /      faster cast to the arrow, but is not an
                         /  /       ideal setup)
------------------------/--/
Belly of the bow

The more normal method to recurve a bow is to hold the area to be recurved 
over a pot of boiling water for quite some time, so that the steam slowly
softens the wood fibres. After a while (20 minutes or more) the wood fibres 
will have softened enough for the limb to be fairly flexible. Shape it to 
the desired shape (Usually by wrapping it around something so as to give a 
uniform curve) then allow it to slowly dry and cool. Ensure that both limbs 
are recurved to the same extent, again ensuring that the curves in both 
limbs match at all times. Any mismatch in the flexing of the limbs will 
place an increased and unbalanced strain elsewhere in the bow, possibly 
with fatal effects (for the bow).

Straightening
=============
Staves made from twisted timber such as Osage Orange, can be straightened
with careful application of heat from a gas stove provided that the timber
is protected by application of fat or candle wax or similar to prevent
burning.

This method is also used to straighten bows which have developed curves or 
twists during use. Carefully and slowly heating the complete bow allows 
the wood to become slightly softer, the wood can then be curved to the 
desired shape and slowly cooled again. The whole bow should be warmed at 
the same time, not in stages, so this can be done in a section of pipe with 
the ends closed, and the heat applied to the pipe, rather than directly to 
the bow.
As long as the wood is not overheated or burned at all, it should return to 
straightness and recover most (if not all) of the lost poundage. This will, 
of course, not be permanent, but can greatly enhance the effective life of 
the bow
-------------------------------------------------------------------------------

Easy Rawhide bow backing
========================
     (From: "I. Priestnall" <priest@netland.nl>

I have found a good source of rawhide for backing bows in the local pet 
shop. They sell rawhide doggy chews that are about 18 inches long, 
composed of a tube with a knot in each end, looking rather like a shabby 
femur bone. Other pet shops I have asked knew about these large chews and 
were prepared to order them for me.

The first task is to choose good material. These chews are a sort of 
dirty buff color. Reject those with obvious flaws, such as splits, and 
try and get hold of those with an even coloration. They are translucent, 
so surface blemishes show through, but I haven't experienced problems, 
even with quite thin areas in the material.

In order to un-knot them, you have to soak the whole chew in cold water 
for about 2 days. The knots in the ends then come undone quite easily. My 
chews consisted of one single piece of rawhide about 36 inches long, 6 
inches wide, rolled into a tube and packed with other bits of rawhide 
about 6 by 11 inches.

Once the pieces of hide have been separated and while they are still 
soaking wet (they are now white and sort of blubbery), you can smooth the 
surface. The hair side is usually ok, but the inner surface can be a bit 
rough. I clamp a steel straight edge in a vise and just draw the surface 
over the steel edge a few times. This scrapes off a lot of loose-hanging 
bits.

Next put the rawhide you will be using into a bath containing cold water 
with about 2 ounces (a scant handful) of washing soda per gallon 
dissolved in it. Leave for 24 hours to degrease the hide.

Take the hide out of the bath, rinse it quite well under running water 
and then roll it up in damp sacking for 24 hours. This renders it damp 
enough to work with, but not wringing wet.

I have backed both board bows and stave bows with rawhide. Stave bows are 
easier due to their lightly rounded back, so I shall deal with them first.

The best glue to use is hide glue. It works like a charm. Put a handful 
of hide glue granules in an old tin can and allow it to soak overnight in 
just enough cold water to cover it. If you don't have a glue pot, cover 
the bottom of a saucepan with marbles or pebbles so as to support the tin 
can free of the bottom during heating. Fill the space between tin can and 
saucepan with water and heat the whole contraption until the glue is 
fluid. Thin with water to get a syrupy consistency. Stir well. Take the 
stirring stick out of the glue and watch the glue dribbling off it. If it 
drips in splashes, the glue's too thin. If it doesn't flow easily - too 
thick. A thin, consistent stream is about right.

Take your bow and clean up the back with fine sandpaper to give a clean, 
grease free surface. I usually wipe it over a couple of times with a 
cloth soaked in acetone to ensure really grease-free conditions.

It helps if the bow is mildly reflexed before backing. Tie a stout cord 
to the nock ends, take a loop over a screwdriver or other lever in the 
middle of the cord, and twist the lever to cinch up the bow into about 2 
inches of reflex. Tie off the lever to the cord. Mount the bow in a bench 
vise with the reflexed back uppermost.

As soon as the bow is clean and grease free, paint a thin layer of hot 
glue over the back surface to seal and prime it. Allow the rpiming coat 
to cool and set (overnight).

Meanwhile, you can cut the rawhide to shape using a hobby knife. Do this 
on a clean surface because you don't want dust and grit on your wet 
rawhide. Allow plenty of overlap over the sides of the bow as the hide 
shrinks as it dries.

The hide will have to be jointed, preferably under the hand grip. I use a 
skiving joint like this:

      ________ __________
              \\
               \\
      __________\\_________

where the overlap is about 0.3 to 0.4 inch. I've done it in two ways: the 
proper way, where you bevel the mating edges of the damp hide using a 
sharp hobby knife before you apply the backing. And the lazy way: Back 
half the bow. After about a day, bevel the glued down backing at the 
joint and back the other half of the bow, using a generous (1 inch) 
overlap. When the backing is dry, you can grind / sand / rasp off the 
excess, leaving a neat surface.

Backing the bow is a simple operation. Get everything ready before you 
start. Make sure the glue's nice and warm and running like table syrup. 
Paint a thin layer on the back of the bow, running down over the sides. 
Place the backing strips in place on the bow, starting at the centre and 
smoothing towards the limb tips. Glue the joint. Don't worry that the 
glue gels almost immediately: the dampness in the hide causes the glue to 
swell and form a bond.

Now take a bandage, minimum 2 inches wide (as used for first aid) and, 
starting at the handle, bandage the bow and backing tightly. Overlap the 
turns of the bandage by about an inch. Fasten off the limb tips tightly 
with a string whipping. Just to make sure, I now usually use a second 
layer of bandage over the first.

Restrain your impatience. Remove the bandage layers after 48 hours. 
Re-whip the joints and the nock ends with string. Allow the bow to dry 
out for at least a week. A month might be better. Then remove the 
whippings and the cord used to strain the bow into reflex.

The rawhide is now as hard as finger nail. Carefully trim off the excess 
using a hook knife (as used by carpet / lino fitters). Rough edges can be 
trimmed with a Surform, and final trimming is done with a spokeshave, set 
for a fine cut.

Allow the bow to cure for about another month before finishing it. I sand 
off the rawhide surface with fine-grit paper, giving a very smooth 
surface, before decorating and varnishing the bow. I use yacht varnish. 
Several coats, sanding between coats. Pay particular attention to the 
sides and the joints, where rain can seep in.

You can also use the same technique with other parts of the bow. Since my 
last bow was only 3 millimeters wide at the nock ends, I fashioned nocks 
from a thin strip of wet rawhide, folded over a thin piece of wooden 
dowel, then glued and whipped on. Nock-shoes and arrow plates can also be 
made.

Backing a flat-backed (de-crowned or board) bow is similar, but I have 
found it useful to use a pressure distributor in the form of a strip of 
aluminium with a T-shped croos section. I place this with the wide flat 
area in contact with the bandaged back, then tie up the whole works 
tightly with cord.

Be aware that, when varnished, the rawhide backing goes almost 
transparent. So you can see the wood grain through the backing. You can 
also see any air bubbles and imperfections in your glueing technique!

I have found a rawhide backing to be immensely strong. It also recovers 
fast: when just unstrung, you can see the bow visibly creeping back to its 
normal conformation. If it has a drawback, it's that it is relatively 
heavy and doesn't add to the bow's cast. Set against that, it's like 
armor plate, and protects the bow against dings and scrapes, as well as 
other archers who may want to 'have a go' with one's pride and joy. 

-------------------------------------------------------------------------------
Recommended reading
-------------------
The Traditional Bowyers Bible - Volume 1 & Volume 2, Volume 3
      Bois d'Arc Press, P.O.Box 233, Azle, Texas 76098
      tel.: (817)237-0829. about $25-$29 each
(if you want to do much bowyery, these are definitely worth the money !)

"Longbow - A social and military history", by Robert Hardy, 
      published by The Mary Rose Trust, Portsmouth.

"The book of the longbow" by R. Elmer and C.A. Smart, published by
      Doubleday.

"Native American Bows" by T.M. Hamilton, edited by Nancy Bagby, published by
      George Shumway, York, Pennsylvania, 1972.


"Building Robin Hood's Longbow" by Jelen Maciek, a 2-part article from
	the US magazine "Traditional Archery", 1985.

"Basic Bows" by A.S. Clarke, a 2-part article published in the July/August
	and September/October 1986 issues of the Australian archery 
	magazine "Archery Action".

Thanks to the following for their help
--------------------------------------
      EDUCC@lure.latrobe.edu.au (Lyn and John Clark)
      akarpowicz@mta.ca (Adam Karpowicz)
      melin@hlrserv.hlrz.kfa-juelich.de (Stephan Melin)
      txhkbcb@grove.iup.edu (Eric Kriley)
      sunfire@muskoka.com (Stephen Fraser)
      priest@netland.nl (Ian Priestnall)


Final thought
-------------
If you want to make a few bows like this, make sure that you have access to 
an open fire or wood stove. The process seem to generate a lot of waste wood 
(in broken staves etc  :-)  ).
Expect to break quite a few of your first trials, trying to get them right.

Good luck !

Any queries, changes, additions or abuse for this section of the FAQ to

Rob McNeur
Rob@ccc.govt.nz

<the end>
Edited by Mark S. Harris	construct-FAQ