Reply To: Woodworking and Sportive Archery
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Here comes the string jig and the tiller tree, as well as a spine tester.
The jig is made from an old “sprung slats” (which according to my dictionary is the correct translation of “lattenrost”, a frame to support the mattress in the bed. All parts can be rotated to store it away. The beams with the aluminium rods need to be rotated while making the string. This jig is used to make an “endless loop string”. There are several holes to move these beams for different string sizes. I made a recess on the “legs” to accomodate the screw heads.
The tiller tree is just a piece of wood with nails and a recess on top, so the bow cannot slip forward. The bow is pulled to a height of 40 cm, which is about 16″. This is as much as I dared to pull it when I built it. Now, that I am shooting it, I pull it out to 29″, which is my regular draw length. The lower limb (left side) is bending way too much near the handle. Both limbs don’t bend at all at the ends. I think, the upper limb is okayish though. Working more on it would have decreased the draw-weight a lot, and I didn’t want that, it is less than 18 pound now, and that isn’t much. The bow actually shoots straight and consistantly. For a first try, I am happy! By the way, it is important to have many stops for the string, because you need to work in small steps. Otherwise, the wood might stay bent and the bow will be weaker. The aim is not to make the strongest bow possible, but to get to a draw weight suitable for the bow and for the archer that will use the bow. English longbows were incredibly heavy, up to 120 pound, but they were intended to penetrate heavy armor of grouped frenchmen. If you shot enough arrows, some would eventually hit and this would hopefully intimidate some of the other side. Aiming was quite difficult, because you cannot hold such a bow for seconds. Well trained sports archers today use bows up to 45 pound only, which is a good compromise between precision aiming and a predictable flight of the arrow. A beginner’s bow should have a draw-weight of no more, better less than 25 pounds. And even that is a challenge to many completely untrained people, men and women alike!
The last image shows a make-shift arrow-spine-tester. The spine of an arrow is a measurement of its flexibility. The arrow is supported on two sides, distance 26″ and pulled down with a weight of 2 pound (in this case a bottle filled with water). The bending is measured in inches x 100, and that is the static spine of the arrow. My ruler measures centimeters, but I only wanted to compare the arrows that I got, and they are all the same (19 mm). Spine, weight, center of mass and length of an arrow are very important values and need to be adopted to the bow and archer. If the values are too far off, the arrow will wobble a lot and might even break on impact, it will not hit the target and it can be quite unpredictable. A too weak arrow will break, when shot. This is dangerous for the archer and also for the bow.
I am not telling you this to brag about my knowledge about archery, but to demonstrate, that it is important to know something about the use of a device, before you make it. This also applies to any field of crafting. A spoon that is beautifully light, carved to a thickness of 1mm, might look fantastic, but will probably not survive the first bite. I didn’t know much about archery when I made the tiller tree, and so it is way too short. At least, it was strong enough… The other two devices were made with more knowledge and they do their job just fine. I’d say, even an industrial high-end string rack won’t produce better strings than mine. It only looks better and has more comfortable adjustments. But it also costs about 20 times as much as mine!
Dieter