📓 INTERACTIVE CALCULATOR

Deep Hole Drilling Cycle Time Calculator

Enter hole depth, drill diameter, cutting speed and feed — get spindle RPM, feed rate, and machining time for a continuous gundrill or BTA pass.

CALCULATOR

Cycle Time

Hole depth L (mm)

Drill diameter D (mm)

Cutting speed Vc (m/min)

Feed f (mm/rev)

L/D depth correction

L/D ratio (for reference)

—

RPM

Spindle speed

—

mm/min

Feed rate

—

min

Machining time

—

holes/hr

Throughput (continuous)

Assumes a single continuous pass — the correct way to drill deep holes. Add ~5–10% for coolant-on ramp, retract and part handling in real production.

FORMULAS

Spindle speed n (RPM)= Vc × 1000 / (π × D) × K_lv

Feed rate Vf (mm/min)= n × f × K_lf

Machining time T (min)= L / Vf

Throughput= 60 / T (holes per hour)

💡 Depth correction: speed is scaled by the L/D speed factor (K_lv), feed by the feed factor (K_lf). Full table in the Feeds & Speeds guide.

⚠️ Don’t peck: gundrills and BTA cut continuously. A peck cycle is a cycle-time penalty and a chip-management failure. See Gundrilling Process.