Boring bar apparatus

In one advantageous embodiment, an apparatus may comprise a boring bar, a slot, a channel, a centering pin, and an adjustment system. The slot may extend substantially perpendicular to an axis extending through the boring bar. The slot may be configured to receive a cutting unit. The channel may be located within the boring bar extending substantially along the axis. The centering pin may be moveably located within the channel and configured to selectively engage a centering feature in the cutting unit. The adjustment system may be configured to position the centering pin relative to the channel in a plurality of axes.