Step 6: Measure and Drill Center Hole
9.5 inches from the other end, mark and drill a hole on the same side as your (wider three) tuner holes. I recommend again using a pilot drill bit, and then switching to a larger bit, drilling half-way in, flipping over, and drilling the rest of the way through *(to prevent splitting.)
It is crucial that you make this hole absolutely centered. There should be no less than 3/16ths of an inch wide on either side.
If it is off centered, or if the hole is very close to the sides, there is a risk of the wood snapping when it becomes time to spread and glue. Additionally, if the sides are too thick, say, larger than 5/16th of an inch, there is also a risk of the wood snapping. Go figure. Therefore, it is always possible to trim up the sides before the step where we spread and glue, but be careful not to cut it too thinly.