Drilling in increments, withdrawing the bit between each to clear chips.
Deep holes trap chips, and a trapped chip is what breaks drills. Pecking clears them, at the cost of cycle time and of repeatedly re-entering a hole that may have work-hardened at the bottom.
The rough rule is to peck once depth exceeds about three diameters in steel. In gummy materials peck sooner; in free-machining grades with good chip formation you can go deeper.
Pecking too aggressively on stainless or titanium, which work-hardens the hole bottom each time the drill re-enters and rubs before it cuts.
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