Bark stripper

Those who are interested in traditional and primitive archery may find themselves wondering how the ancients made bows and how Stone Age man managed to fashion weapons that equal the modern fibreglass weapons sold in hunting and archery stores. The answer is that the ancients often made their bows from green wood with minimum effort, using stone tools that are better suited to bow crafting than our modern metal tools. In this series Pedro Victor explains how one can craft one’s own bow from green wood.

Making the bark stripper
To assist with bark stripping, one of the trickiest jobs when crafting bows from green wood, I have developed a simple tool which I name the bark stripper. To make one you will need two lengths of 20-centimetre long broomstick or sections of tree branches about 15 to 25 millimetres thick and one length of thin 0,5- to 1-millimetre thick wire of about 30 centimetres in length. Ordinary baling wire is not suitable as it tends to break. Guitar strings and piano wire are more durable materials, but also tend to break with use.
Simply drill a hole through each of the broomstick sections, at the centre of the section. Then pass the wire through the holes and tie it in place by twisting it around the handle and knotting it by whatever means you prefer. You will have a device that resembles a garrotte.

Bark stripping
To use the bark stripper, first carefully loosen the bark at the end of the stave using a knife such as an okapi. Preferably the stave would already have been reduced to rough tillered dimensions, resulting in the bowyer only needing to strip bark from a relatively small section of the original stave.
Try to raise the bark evenly at the edge so that the wire can be slid underneath the bark for the entire surface. With the stave secured in a vice and the bark facing away from you, lightly pull the handles towards you and press downwards simultaneously. The wire should slide between the inner bark and the wood, stripping the bark away cleanly. This is usually the case for fresh, late summer cut staves. Once autumn gets in its stride, the bark starts adhering to the wood, complicating the process and meaning that bark may come off in small strips instead of one or two large sections. Inner bark fibres may adhere to the wood, even with summer harvested staves. Rubbing the back of the bow blank with a flat edged (square) piece of wood usually removes these fibres without any serious scratches or nicks to the back.

The okapi knife is very useful for stripping winter cut staves. Work the knife blade under the bark from the edges of the stave, wiggling the knife under the bark to the centre. Do not slant the blade down into the wood, but let it slide under the bark and wedge the cutting edge upwards against the bark.

Tillering
The tillering process is perhaps the most difficult and complex part of bow crafting. Tillering is the act of removing wood from the bow’s belly in order to make the bow bend without breaking. The word “act” and not “art” has been used to describe this process. Tillering is not an art; it is not a mystical practice and can be comprehended and practised by a beginner. Just remember that one inch is 2,54 millimetres.

A particular bow wood, when shaped to specific dimensions, will result in a bow of specific tiller (bent shape) and draw weight. The draw weight may vary slightly depending on the number and density of growth rings, but this should almost always be a very slight variation. A bow shaped from white woods such as white stinkwood, oak or elm should have the following dimensions: limb width: 40 to 75 millimetres; limb thickness: 15 to 23 millimetres.

Within these dimensions it is possible to produce bows with light draw weights of around 30 pounds (13,61 kilograms) to heavy war bows of 90 pounds (40,82 kilograms) or more. Halving the width of the bow reduces draw weight by half; halving the thickness of the bow reduces draw weight by a factor of eight. Half the thickness equals an eight times reduction in draw weight.

The easiest handle to shape is a non-bending handle, about 30 millimetres thick and around 25 millimetres wide. The handle can be made thinner but it requires some experience to be able to judge the minimum thickness for the wood. Always ensure that the wood thickness begins to taper off only at the point where the bow has widened to the inner limb width. The handle is thus a thicker but narrower section that becomes thinner only at the point where the handle has already faded into the limb.

Checking string nock alignment: Use a length of thin cord or cotton string. Slide an elastic band over the string, wrapping the elastic around the nock area. Pull the string until the opposite end can be similarly attached to the other nock area. The string should now run in a straight line from nock to nock and bisect or pass through the centre of the handle.

A tillering string is required to tiller a bow. This can be made using a length of washing line rope and two rectangular pieces of leather, as shown in the photo.

A tillering stick should also be made using a plank, 40 by 60 by 1 000 millimetres minimum. Mark intervals of one inch on the 40-millimetre wide side of the plank, then drive long 70-millimetre tech screws in, centred on every inch mark for 30 inches. One inch is 2,54 millimetres. Leave the tech screw head protruding about 20 millimetres from the wood surface. The bow can be set on the top of this plank and drawn using the tillering string, which can be hooked onto any of the tech screws so that the tiller can be observed. Resting the tillering stick on a bathroom scale and drawing the bow on the stick also allows an accurate assessment of draw weight at any given draw length.
It is best not to tiller using a drawknife or block plane as these can tear up splinters and ruin a bow. Only use a coarse or medium rasp and a sure-form tool. The coarser the rasp, the greater the chance of it tearing wood splinters from the belly. Experimenting with a scrap piece of the particular bow wood will indicate how prone the wood is to chipping and tearing with your tools.

Remove wood evenly from the belly, using the rasp. The idea is to have the bow with an even thickness throughout its limbs. This is done by rasping evenly across the belly, most often at an angle of up to 45 degrees, but depending on the wood type it may also be practical to rasp at 90-degree angles. The purpose of the initial wood removal is to get the rough tillered and dried stave to bend again. Floor tiller the stave by pushing one nock end on the floor and applying pressure to the handle from the belly side. When the bow begins to bend when significant force is thus applied, it is floor tillered.

To continue the tillering process the nock area should be roughly shaped and the tillering string mounted over the nock area. The bow can now be bent on the tillering stick. Draw the bow for the first few inches, not more than five, and check the draw weight on the scale. For the first ten inches of the draw length one can tiller to a draw weight of 20 per cent below the final desired draw weight. For example, a 50-pound bow can be tillered at 40 pounds until the tenth inch of draw.
Thereafter measure the draw weight on the scale to the desired final weight but never above that weight. The reason for this is that it reduces the risk of bow failure for the first critical inches wherein the bow stave is thickest and at greatest risk of failure. Remember that the bow tips do not bend to the same length as the draw length, which is the distance between the nock point on the string and the bow handle.

Once the bow is drawn on the tillering stick one is able to see the curvature of the limbs. Traditional European archery teaches that the limbs should bend evenly throughout the draw and this produces a more efficient bow, but need not be the case at all stages of draw. It also makes tillering easier and simpler. Certain bows have reflexed lower limbs and deflexed upper limbs. In such bows the limbs do not bend equally at all stages of the draw.

In the case of a symmetrical straight stave bow, pay careful attention to the shape of the bent limbs and try to ensure that the bend is symmetrical throughout the draw.

The Holmegaard weapon is ‘round in the handle’, but the handle of a Holmegaard does not bend at all. A Holmegaard is round in the limbs. It simply has non-bending outer limbs, which for the purpose of explanation are best described as long non-bending tips.

The tillering process involves the continued removal of wood from the limbs of the bow. At each stage the bow is drawn or bent an inch or two more on the tillering stick and the curvature of the limbs is checked for symmetry and form, which must correspond to the desired shape for the specific design. At the same time the draw weight is checked and wood removed from the belly until the bow draws to the required draw weight. As the bow is bent or drawn further, the bowyer should take care to remove progressively less wood. This means fewer passes with the rasp and perhaps using a finer rasp. During the final six inches of draw length wood removal must be done very carefully indeed, culminating in the use of a bastard file and cabinet scraper rather than a rasp. Although this is more time consuming, it reduces the possibility of error for beginner bowyers.

Burnishing the bow
The process of burnishing is extremely important for crafting durable self-bows. This process is sometimes elevated to a semi-mystical bowyers’ art. Burnishing is simply the act of compressing the wood fibres on the surface of the bow. The back of a self-bow must be burnished, and it is preferable although not essential to burnish the belly. One does not need a boar’s tooth or some strange and specialised tool to burnish a bow. A screwdriver with a smooth shaft and a diameter of about seven millimetres will work very well indeed.

Apply masking tape over the tip of the screwdriver to prevent accidental scratching and nicking of the bow in case of slippage. Rub the bow with the screwdriver shaft, applying pressure and using short back and forth strokes about 30 centimetres in length. Keep the portions of the bow being burnished below shoulder level to ensure good leverage and constant pressure. Uneven spots may be burnished using burnishing stones. Any smooth, hard, rounded and polished stone, as sold at craft or flea markets can be used, simply ensure that the stone’s shape meets your specific requirements.

The bow surface begins to shine as the process continues and the wood fibres are compressed. Once the surface is shiny, proceed with longer strokes to ensure a more even surface. Burnishing can take from an hour to several hours but is invaluable in producing a durable weapon.

Finishes and staining wood
When using the green wood technique, the back of a wooden self bow does not usually have to be sanded. If the craftsman prefers to sand the back then it is best to use fine-grit sandpaper and work carefully. Bows made from heartwoods will almost invariably require sanding, which is another reason for the beginner at least to craft bows from white wood. The belly is always filed and sanded to remove the rasp tool marks.

The methods for sealing and protecting the bow are many, but can essentially be divided into two categories: traditional and modern or synthetic.

The most ancient methods involve the application of molten or semi-liquid animal grease (cooked fat) to the bow surface. A butcher should be able to provide pig fat, which is then cut into small blocks and added to a small quantity (half a cup) of water in a small pot. Allow to boil. The water boils off and the pig fat cooks in the molten fat created initially. The bowyer is then left with a liquid fat that can be rubbed into the wood with a soft cloth. This grease will set when it cools and can be refrigerated in a jar for future use.

A mix of 45 per cent paraffin, 45 per cent bees’ wax, and ten per cent linseed oil when heated together will also produce a sealant that can be stored dry, melted and applied as a finish.

The modern method is better and indispensable for South African conditions. Bows intended for use outdoors for long periods, such as in hunting, are best sealed with polyurethane varnish. Our primary concern is actually not to seal the bow from moisture, but rather to prevent moisture escaping from the wood, thereby rendering the wood too brittle for use in a bow. Woodoc No. 25 is a good local polyurethane varnish. It can simply be painted on using a brush as per the manufacturer’s instructions. Alternatively, an airbrush might be used although I have not experimented with this method. See the section on relative humidity and South Africa for more details.

Various techniques can be used to stain the bow or bow blank. These range from modern aniline dyes to simple bark staining.

Bark staining involves the removal of the green bark, preferably in one or two pieces using a bark stripping tool. The inner bark contains tannins that naturally stain the wood. Simply secure the strips of stripped bark using elastic bands and leave the bow to stand for about a week. Allowing the wood to dry out slowly after the week has passed, adds to the staining effect, so it is best to keep such a stave in a humid environment or cover it with plastic bags for an additional week. Covering the bow back in this way also reduces the chances for cracking and checking on the bow’s back.

Various natural dyes can be used. Berry juice apparently yields fairly good results. An even better method is to use powdered bark, perhaps reduced in a coffee grinder, or tea leaves boiled in water to make a paste that can be applied to the bow. Allow this to stand in a moist environment or sealed in plastic for a few days so that the tannins stain the wood.

Paint can also be made by boiling tannin-rich wood such as red karee for at least four hours. The water boils off (after several top-ups) to produce a red brown paint.

Aniline and other manmade dyes are commonly used and any reputable hardware or woodworking store should be able to provide a range of wood stains for use by the craftsman.

Polyurethane varnish can also be pre-stained or coloured by the addition of a small amount of stain or dye. This is the best finish in terms of the efficacy of the sealing surface.

For any enquiries related to wooden bow crafting or to discuss the possibility of classes contact Pedro Victor on 083 7033966.

For enquiries about custom made knives and edged tools such as draw knives and adzes please contact Chris Botha on 0835230817 or visit his website: http://www.blademarket.co.za/.