← AskMachinist · Guides · Calculator · 🔎 Search
Peck Drilling Basics
Guide · Updated October 28, 2026
Peck drilling breaks a deep hole into short steps so chips can clear and coolant can reach the tip. Done right it prevents packed flutes and broken drills; done too often it just wastes time.
Start from a good spot
Spot first, then peck. Check hole locations with a height gage set from the free Gage Block Calculator.
Step by step
- Check depth: Holes deeper than about 3× drill diameter usually need pecking; under that, drill straight through.
- Spot first: Spot drill the location so the drill starts true.
- Pick a peck: Start with a peck of about 1× diameter, and reduce it as the hole gets deeper.
- Choose the cycle: Use full retract (G83) for deep holes that pack chips, and chip break (G73) for stringy materials in moderate depth.
- Use coolant: Use coolant or cutting oil and clear chips at each retract.
- Watch the sound: Squeal or a rising load means packed chips; peck shorter.
- Finish: Deburr and check depth.
Worked example
1/4 in drill, 1.5 in deep (6×D) in steel. Start pecks at 0.25 in, cut to 0.15 in past 1 in deep. On CNC: G83 Z-1.5 Q0.25 R0.1 F3.0.
Parabolic flute drills
Parabolic drills have wide flutes that move chips well, so you can often drill 5–7×D with fewer or no pecks.
Manual mill tips
On a manual mill, raise the quill fully every few pecks to clear chips, and don't let the drill dwell at the bottom.
Tips
- Get speeds right: drilling speeds and feeds.
- Spot first: center and spot drilling.
- Pick the right tap drill: tap drill chart.
- Coolant matters: cutting fluid basics.
FAQ
When should I peck drill?
Usually for holes deeper than about 3 times the drill diameter, or in materials that pack chips.
What is the difference between G83 and G73?
G83 retracts fully to clear chips; G73 retracts a small amount to break chips and is faster.
How deep should each peck be?
Start around 1 times the drill diameter and reduce it as the hole gets deeper.
Do carbide drills need pecking?
Through-coolant carbide drills often drill deep without pecking; non-coolant ones may still need it.
Why did my drill break while pecking?
Packed chips, too long a peck, too much feed, or poor coolant are common causes.
Related guides and calculators
- Drilling Speeds and Feeds
- How to Center Drill and Spot Drill
- Tap Drill Chart Explained
- Tapping Speeds and Feeds
- Cutting Fluid and Coolant Basics
- Reamer Speeds and Feeds
- Countersink and Counterbore Basics
- Tool Length Offset Basics
- How to Ream a Hole
- How to Drill on a Mill
- How to Sharpen a Drill Bit
- All free machinist calculators
Build your stack in seconds
The free Gage Block Calculator finds the fewest-block combination for inch and metric sets, with wear blocks. No login.
Questions? Ask a machinist.
General shop information only — follow your machine and tooling manufacturer's instructions and your shop's safety rules.