How do I locate the spine of the blank?Updated 3 years ago

There are tools on the market, referred to as "spine finders" that allow you to do this quickly and easily.

https://mudhole.com/products/crb-spine-finder-deflection-system-crb-sf

Find a blank's spine without a spine finder tool

Place the butt of the blank on a smooth surface. Support the extreme tip end with the fingers of one hand. With your other hand, apply pressure to the middle area of the blank. Put a decent bend in it. As you do this you will find that the blank attempts to roll into a position where it wants to stay put. Any attempt to move the blank out of this position, while it is under pressure, will result in the blank trying to remain or returning to this same position. The OUTSIDE of this curve is referred to as the "effective spine" and should be marked for reference.