Preparing the bow for shooting part 3 CHECKING THE GEOMETRY - axial symmetry and balance of limbs.

As we told in the previous part, we should perform first check of bow geometry immediately after bracing, when we still hold it firmly under control. However, with a bow supported under one's leg or below knees it's a bit hard to see all imperfections of its shape except those most obvious. When we can take it loosely in the hand, it's time for a closer look.
First we should once more take a look on string loops; we already checked that they are properly attached and laying in the middle on the limbs, but now make sure that they are EXACTLY centered and not twisted. Make corrections if needed - there is no point to go further with our checks, if loops are not properly aligned.
Loops have strong tendency to twist if the string is poorly build or it's main part is overtwisted (more about this later).
If our string is of more traditional design, with loops formed by knots, we should also make sure that those knots are laying correctly, so their free ends are sticking outside of the bow and not pressed against it's belly side.



Now we should position our bow in such a way, that we can look along the string, first from one, then the other. Braced string makes a perfectly straight line, against which we can easily spot if the limb tips are laying exactly along bow axis, or escaping a bit left or right. Some slight deflections just after the bow was stringed are perfectly normal and nothing to be afraid of. You should worry only if the bow is not "responding" to corrections or the problem is coming back (or developing worse) after several shoots.

Holding the bow in one hand, we grip the misaligned end of limb with the other, from underside, with fingers pressing the string loop against bow belly to keep it in place. Now we press with the base of our thumb to push limb tip to the side, in opposite direction to existing contortion. You shouldn't push too far; it will be easy to adjust the limb tip several degrees (more or less, depending on bow design), but as soon as we feel the material starting to resist further bending and stiffen, we should stop and hold it in this position for several seconds, then release and check alignment. It should be better. If not perfect, we can once again push the limb tip, never more than the first time, but holding a bit longer if necessary.
Sometimes we can overshoot a bit and then have to push the limb tip back in opposite direction. Please note that - depending on what direction we would like to push - it will be better to hold grip of the bow with left hand and limb tip in right hand, and sometimes just the opposite. Normally after no more than 3-4 left-right corrections we should have one limb exactly centered, then we start working on the second limb.

When center axis is done, we should look at our bow from the side. Most often we deal with almost-complete-symmetrical designs, meaning that both limbs are identical or very close in length and they should bend almost the same. Just after stringing, especially if we strung it by our self "across the leg", instead than with a helper, we can often find that despite our best efforts one of the limbs is bending a bit more than the other. In such a case we take this "weaker" limb in the hand in such a place, that we can reach the string with our fingertips and squeeze, pulling it closer to bow belly. This causes the limb to straighten and the opposite, "stronger" limb to bend more. We can do this quite vigorously, as it is much safer to adjust the limbs along bow axis than to the side. After several seconds we release our grip and check geometry again.

In case of especially "stubborn" pieces we can pull the string towards one limb and hold it there for as long as necessary by wrapping it with bow's own protective sleeve or some other strap, wide enough not to mark its surface.

There are also some asymmetric bow designs, with upper limb longer and more flexible than lower (most extreme case is of course traditional Japanese yumi). In those cases examining bow geometry is much more difficult as an archer have to learn "how the bow should look like" in a particular design.
Even in the case of almost-completely-symmetrical bows, the key word is "almost". In fact, because archer's bow-hand anatomical build is not symmetrical, the limbs of most bows (excluding modern compounds and some other very special cases) are designed to bend just a little bit uneven, top limb slightly weaker. So, when we succeeded to adjust limbs to, at face value, proper bend, we should proceed to set so called "tiller" - meaning final, precise adjustment - more about this in the next part.

Please note, that so far we spoke mostly about the amount of bend each of the limbs is taking, not about their actual shape. That's because as long as we are dealing with bows made of modern materials, utilizing fiberglass or carbon fibers, limb shape is almost always correct. If some part of the limb is bending more than it should, we can expect it to be cracked or delaminated, in need of a major repair (and often damaged beyond any hope). Owners of "natural" composites have much more fun with their bows requiring a lot of pressing here and there, rubbing the horn layer by hand or heating some specific sections over traditional charcoal fire or more modern electric stove, until proper shape for the particular design is achieved.

In the next part we will proceed to the next point in checking the geometry: tiller