Drilling Centered Holes in Spheres
In my high-school woodshop class, we needed to drill 1/2-in.-dia. holes partway through 100 1-1/4-in.-dia. hardwood balls. I suggested to the instructor that we clamp a board to the drill press table and bore a 3/4-in.-dia. hole in the board to serve as a socket to hold the ball being drilled. Then we chucked a 1/2-in.-dia. Forstner bit into the drill press and set the stop to the desired depth. One student held each ball while another drilled. Each hole was perfectly centered. This technique worked so well that my instructor suggested that I submit it to the Methods of Work column. Many of the methods shared by readers of Fine Woodworking have been put to good use in our shop and I hope that this idea may be useful to another woodworker.
Heather Groff, Vida, Ore.
Fine Woodworking Magazine, June 1991 No. 88