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Making your own bow part 8: Tillering and final finishing
In this article of his series on bow building, Cleve Cheney gives instructions on how to tiller a fibreglass laminated bow, as well as how to do the final finishing.
Now before we can get to the final finishing we must tiller the bow – a very important step that we must not attempt to bypass in our excitement to want to shoot our creation! Tillering comprises the gradual bending of the bow over a period so that the glass and wood fibres can have time to orient and 'bed' themselves. If this is done gradually the bow will not break. During the tillering process it must also be established that the limbs are bending equally and in the same places and are not twisting.
> Figures 1 & 2
A tillering stick consists of a block in which to lie the bow handle, an upright with notches cut into it every one inch (25 mm) for 30 inches and a stable stand (see figure 1). String the bow and place it in the tillering stick as illustrated. The string is drawn down a few inches. Look at the bend of the bow. It should be bending at the same places and bending uniformly (see figure 2).
If one side is bending more than the other, slowly remove wood from the side that is bending less by narrowing the limb until the bend in the bow is uniform or remove wood from the belly. Flex the bow about 20 times after each time wood is removed. Over a period of up to four days the bow is gradually bent further. Time must be given for the fibres to orient and program themselves.
Leave the bow flexed for a few minutes each day at different draw lengths, progressing slowly further each day. Test the poundage regularly and stop removing wood when the bow can be drawn to at least 28 inches and you are happy with the poundage. Tiller is the distance between the upper and lower limb measurements from the bowstring to the belly at the fadeouts. Bows are traditionally tillered to produce a stiffer lower limb. Remove wood slowly when you are tillering the bow. You can always take off more but you cannot put it back. If you take off too much the bow will end up having a very low poundage. At this point you should have a functional bow, but there are still a few things to do. The first is an arrow shelf / sight window.
< Figure 3
When the arrow shelf has been cut, beveled and radiused check the tiller once again and if necessary remove what wood is necessary to ensure that the limbs are bending evenly and uniformly - figure 3. Before a finish can be applied the bow must be sanded down with sandpaper making sure to radius all edges. Progress from coarse to fine grades of sandpaper. The bow must end up being smooth - especially the back of the bow. Make sure any blemishes and scratches are removed. Wipe the sanded bow down with a slightly damp cloth to remove all sanding dust and residue. Allow it to dry thoroughly.
You can now use an aerosol type polyurethane varnish to seal and finish off the bow. Not only does the varnish bring out the grain of the wood it protects it from absorbing moisture which can weaken the bow and also make it more likely to twist or deform. Apply at least six coats to the bow. Allow each coat to dry thoroughly then sand it lightly with fine grade sandpaper before applying the next coat. This helps to fill the pores and gives the bow a deep luster.
> Figure 4
The next step is to apply a leather grip to the handle. You will need a piece of tanned calf leather and some leather thong and some wood glue. Cut the leather to the required shape and then punch holes along the edges. Now soak the leather and thongs thoroughly in water. Coat the handle area and the bonding surface of the leather with white wood glue. Apply the leather whilst it is still wet. Stitch the ends together as shown using the leather thongs. Mold the wet leather by hand so that it takes the shape of the handle and allow to dry. As the wet leather dries it shrinks and fits tightly to the wood. See figure 3.
A piece of leather is also stuck onto the arrow shelf itself and extends up the side of the sight window for a short way. See figures 4 and 5. The bow is basically completed and now you have to make a string and perhaps one or two spares for it. We will show you a number of ways to make strings in the next article.
< Figure 5
About the Author
Cleve Cheney, hunting and environmental editor of Africa’s Bowhunter is a very well known figure in bow hunting and in conservation circles in South Africa. Cleve Cheney has been in conservation for 27 years, of which 20 years were spent with the National Parks Board – most of it in the Kruger National Park. During the time spent in the Kruger National Park Cleve culled no less than 50 elephants with a rifle and he has hunted most African game during culling operations.
Cleve has also been an avid bow hunter for 22 years and he has an extensive technical knowledge on bows, arrows and broadheads. Cleve is also an accomplished bowyer and has built many recurves over the years. He began offering bowhunting education courses more than 15 years ago. Until recently, Cleve was a lecturer at the South African Wildlife College where was a lecturer and instructor. He has a diploma in Nature Conservations and a MA degree in animal Physiology. Over the years Cleve has written more than a hundred articles on tracking, hunting, survival skills, and bow and rifle hunting. He started an 18 month long professional hunters course at the SA Wildlife College where he trained the first group of professional hunters.
Cleve has trained many bow hunters and his educative articles on how to hunt African game, as well as many other articles on different aspects of archery bow hunting an bush skills has been published in Africa’s Bowhunter, Game and Hunt magazine, Universal Hunter and many other magazines. He has been the lead article writer for Africa’s Bowhunter for more than 14 years.
His book on tracking, The Comprehensive Guide to Tracking: In-depth information on how to track animals and humans alike, is probably the most in-depth study on this subject available. For those who want to learn more than the basics, this book is a treasure trove of tracking information, insights, methods, and knowledge. The book is divided into logical sections: teaching yourself to track; understanding wildlife behavior; identification of tracks and signs; gait patterns and pressure release; blood trailing; tracking specific animals; track, stalk, and approach; bird, reptile, and invertebrate sign; man tracking; and dangers in the bush.