UnderControl: You need to exercise the limbs each time you remove wood from them in order for the changes to register. This is done first by floor tillering 15-20 times on each limb, then by restringing and drawing it or pulling it on your tillering tree several times, taking care not to draw past the point where your desired weight is met. A scale is critical here. I tillered my first bow by feel and it came in way underweight. It helps to think about how the wood bends. Wood fibers along the back of the bow must stretch as the bow is flexed, whereas fibers along the belly must compress during the draw. Somewhere in the middle is a neutral band of wood that neither stretches or compresses as the bow is drawn. However, as wood is removed from the belly, that neutral zone moves closer to the back of the bow, and wood that formerly stretched is now in the neutral zone. If the bow is pulled back too far and belly wood is then removed, the neutral zone may move so far towards the back, wood that was formerly trained to stretch may now lie in the compression zone. Wood can't handle this drastic change and maintain structural integrity. This is why everyone is advising to tiller by weight, not draw length. If your goal is a 50 pound bow, by making sure you never draw past 50 pounds you will teach your bow to bend incrementally. Each time you remove wood, you will gain another fraction of an inch. Its a time consuming process that can't really be rushed.