CNC Peck Drilling Cycle Calculator: Fanuc & Haas G83 vs G73 Code Generator
In Fanuc and Haas CNC programming, use G73 High-Speed Chip-Break Drilling (micro-retract of 0.25–0.50 mm) for holes 2.5×D to 4.0×D deep to break stringy chips quickly, and use G83 Deep-Hole Full-Retract Peck Drilling (full rapid retract to the R plane with Q = 0.50×D to 0.75×D) for holes deeper than 4.0×D to evacuate packed flutes and flood the drill tip with coolant.
CNC Peck Drilling Cycle Calculator & G-Code Generator (G83 vs G73)
Compute optimal peck depth (Q), variable peck decay (I/J/K), feed rate (F), and verified Fanuc/Haas G83 / G73 canned cycle code.
What Is the Difference Between G83 Deep Peck Drilling and G73 High-Speed Chip Breaking?
When drilling holes deeper than 2.5 times the twist drill diameter (L/D > 2.5), continuous feeding with G81 causes long spiral ribbons of steel or aluminum to pack tightly inside the helical flutes. Once the flutes choke, torque spikes instantaneously and snaps the drill in the hole. CNC controls built on ISO International Metrology Standard (ISO 6983 G-code syntax) and Fanuc/Haas standards provide two distinct peck drilling canned cycles—and choosing the right one cuts cycle time by up to 45% while protecting tooling:
The G73 High-Speed Chip-Break cycle feeds down by peck depth Q, executes a short micro-retract (Fanuc Parameter #5114 or Haas Setting #22, typically 0.25–0.50 mm) to snap stringy spirals, and immediately resumes cutting for holes 2.5×D to 4.0×D deep. Conversely, the G83 Deep-Hole Peck cycle rapids all the way out to the R plane after every Q peck to sling packed chips off the flutes and flood the hole with coolant before rapid-returning to a safe clearance distance (Parameter #5115 / Setting #52, 1.00 mm) above the previous bottom.
| Hole Depth-to-Diameter Ratio (L/D) | Recommended Canned Cycle | 1st Peck Depth (Q Value) | Subsequent Peck Reduction | Retract Clearance (Param #5114 / #5115) | Primary Chip Evacuation Strategy |
|---|---|---|---|---|---|
| L/D ≤ 2.5 × D | G81 Spot / Continuous Drill | Full Depth (No Peck) | None | R-Plane Direct | Continuous flood or through-spindle coolant (TSC) |
| 2.5 × D to 4.0 × D | G73 High-Speed Chip-Break | 1.00 × D to 1.50 × D | Constant Q | 0.25–0.50 mm (0.010"–0.020") micro-retract | Breaks stringy chips without clearing flutes |
| 4.0 × D to 6.0 × D | G83 Deep Hole Peck Cycle | 0.75 × D to 1.00 × D | 0.50 × D min | 1.00–1.50 mm (0.040"–0.060") rapid clearance | Full retract to R-plane flushes chips & cools tip |
| 6.0 × D to 10.0 × D | G83 Variable Peck (I / J / K) | I = 0.75 × D, K = 0.25 × D | J = 0.15 × D per peck | 1.00 mm (0.040") above previous bottom | Progressive peck decay prevents flute packing |
| L/D > 10.0 × D | Custom Macro / Gun Drilling | Pilot Hole + Guided Entry | Continuous TSC (70 bar) | Do not rapid-peck carbide > 8×D | 150° pilot + reduced RPM entry + continuous TSC |
How to Program Variable Diminishing Peck Depths (I, J, K Format) in G83
When drilling deep holes from 5×D to 10×D with HSS or cobalt drills, the first 2×D of depth evacuates chips easily, whereas the bottom of the hole requires progressively smaller bites. As documented in Machinery's Handbook (Industrial Press) and NIST (National Institute of Standards and Technology) machining data handbooks, both Haas and Fanuc controls support an optional Variable Peck I / J / K syntax inside G83 instead of a fixed Q address:
G98 G83 X0. Y0. Z-50.0 R2.5 I8.0 J1.5 K2.5 F350.0
Here, I defines the size of the first pass (8.0 mm), J specifies the amount by which each successive pass is reduced (1.5 mm smaller each peck: 8.0 → 6.5 → 5.0 → 3.5...), and K sets the minimum peck depth floor (2.5 mm) used for all remaining passes to reach target Z depth.
| Drill Diameter (D) | G73 Chip-Break Q (3×D Hole) | G83 Standard Peck Q (5×D Hole) | G83 Deep Hole Min Peck (K Value) | Recommended Feed (4140 Steel) | Recommended Feed (6061 Aluminum) |
|---|---|---|---|---|---|
| Ø 3.175 mm (1/8") | 3.18 mm (0.125") | 2.00 mm (0.079") | 0.80 mm (0.031") | 0.050 mm/rev (0.0020") | 0.080 mm/rev (0.0031") |
| Ø 4.763 mm (3/16") | 4.76 mm (0.188") | 3.18 mm (0.125") | 1.20 mm (0.047") | 0.075 mm/rev (0.0030") | 0.115 mm/rev (0.0045") |
| Ø 6.350 mm (1/4") | 6.35 mm (0.250") | 4.50 mm (0.177") | 1.60 mm (0.063") | 0.100 mm/rev (0.0040") | 0.150 mm/rev (0.0060") |
| Ø 9.525 mm (3/8") | 9.53 mm (0.375") | 6.50 mm (0.256") | 2.40 mm (0.094") | 0.150 mm/rev (0.0060") | 0.220 mm/rev (0.0087") |
| Ø 12.700 mm (1/2") | 12.70 mm (0.500") | 8.50 mm (0.335") | 3.20 mm (0.125") | 0.200 mm/rev (0.0080") | 0.280 mm/rev (0.0110") |
| Ø 19.050 mm (3/4") | 19.05 mm (0.750") | 12.70 mm (0.500") | 4.75 mm (0.187") | 0.280 mm/rev (0.0110") | 0.380 mm/rev (0.0150") |
Why You Should Avoid Rapid G83 Pecking with Solid Carbide Through-Coolant Drills
While HSS and cobalt twist drills rely on G83 pecking to survive deep holes, solid tungsten carbide drills running high-pressure Through-Spindle Coolant (TSC, 40–70 bar) are brittle in tension and thermal shock. Rapidly retracting a hot carbide drill into cold flood coolant and slamming back into work-hardened chips chips the cutting lip corners. For solid carbide TSC drills up to 8×D, run continuous G81 (or G73 with a 0.15 mm micro-dwell) after spotting with an equal or larger point angle! Be sure to include the conical drill tip length from our Drill Point Length & Z-Depth Calculator, verify blind tap clearance on our Blind Hole Tap Depth Calculator, synchronize tapping feeds on our Rigid Tapping G84 Feed & Speed Calculator, and look up exact drill diameters on our Master Tap Drill Chart.