Does BullseyeBore Core need to be centered on the chuck face for proper use?

No, BullseyeBore Core does NOT need to be centered on the chuck face for work surface alignment drilling operations. The work surface patterns from BullseyeBore Core are produced from one side of the BullseyeBore Core arm and thus always produce circular patterns when the drill is aligned with the work surface.

However, there are a couple of conditions where centering BullseyeBore Core on the chuck face (e.g., centering BullseyeBore Core on the rotational axis of the drill) is helpful. First, if your drill is small or lightweight, an uncentered BullseyeBore Core can create an “unbalanced” condition during drill rotation and drilling operations. This can lead to some vibration and/or perceived rotational instability. Second, if you want a consistently positioned Reference Pattern on the work surface with the drill bit at the center, then centering BullseyeBore Core on the chuck face is important.

The simplest and best method for consistent centering of BullseyeBore Core on the chuck face is by using a Standard Chuck Alignment Guide. Please see the Standard Chuck Alignment Guide FAQs for more information, or the Standard Chuck Alignment Guide page.