Set peck depths based on hole depth, drill diameter, and material. Avoid chip packing, breakage, and oversize holes.
Calculate ↓For G83 deep hole peck drilling cycles on CNC machining centers.
The first peck is always the deepest. A sharp carbide drill entering solid material at the surface can take a 2-3× diameter initial peck because chip evacuation is easy — chips exit immediately. Once the hole reaches 3-4× diameter depth, chips must travel up the flute, and the peck depth must be reduced to prevent packing.
For a 10 mm carbide drill in 4140 steel at 40 mm depth, the first peck can be 20-25 mm. The second peck should be 10-12 mm. By the third peck, the depth should drop to 5-6 mm. This decreasing peck pattern maximizes productivity while preventing the chip packing that causes drill breakage.
On a Haas or Doosan drill/tap center, the G83 cycle with a decreasing peck (Q value changing per peck) must be programmed manually or with a macro. Most CAM systems generate constant peck depths — the calculator above gives you the optimal variable peck pattern to program manually.
What is peck drilling? A drilling cycle where the tool periodically retracts to break chips and clear the flutes. G83 in most CNC controls.
How deep should each peck be? First peck: 2-4× drill diameter depending on material. Subsequent pecks: 0.5-2× diameter. Decrease peck depth as hole depth increases.
When should I use peck drilling vs. continuous drilling? For holes deeper than 3× diameter in steel, or 5× diameter in aluminum, use peck drilling. For shallow holes, continuous drilling is faster and produces better surface finish.
Does peck drilling increase cycle time? Yes, by 15-40% depending on the number of pecks. The trade-off is acceptable because peck drilling prevents tool breakage, which costs far more than the added cycle time.