⚡ CUTTING DATA

Feeds & Speeds Tables

Quick-reference cutting parameters for deep hole drilling. Base Vc and feed by material and diameter, then apply L/D correction factors. Separate tables for gundrilling and BTA.

16MaterialsVc ranges

5DiametersFeed columns

10L/D StepsCorrection factors

4FormulasRPM/feed/time/MRR

GUNDRILL

Cutting Speed by Material

Recommended Vc (m/min) for gundrilling. Use lower end for harder materials, higher end for softer.

💡 Indexable-insert gundrills run higher feeds than these brazed-tool values: botek Type 01 / Iscar GD-DH indexable gundrills feed roughly 2× the penetration rate of brazed carbide (TriumphTool, 2024), and Tungaloy’s DeepTri-Drill series is engineered for 1–2 MPa (145–290 psi) coolant at elevated feed. If you run indexable tooling, use the insert maker’s data sheet rather than the brazed-tool tables below.

Material Group	HB	Carbide-Tipped	Solid Carbide
Non-alloy steel <0.25%C	~125	120-180	100-140
Non-alloy steel ≥0.25%C	~190	100-150	90-120
Low-alloy steel (annealed)	~200	60-80	60-70
High-alloy / tool steel (annealed)	~200	60-80	60-70
Hardened steel	~325	40-60	30-50
Stainless ferritic/martensitic	—	40-80	40-50
Stainless austenitic/duplex	—	30-60	30-40
Gray cast iron	—	70-100	60-90
Aluminum (wrought)	—	80-160	100-200
Aluminum (cast, high Si)	—	60-120	80-140
Copper alloy / brass	—	80-150	80-140
Bronze (high-tensile)	—	50-90	50-80
Nickel superalloy (Inconel)	—	15-30	10-20
Titanium alloy (Ti-6Al-4V)	—	20-40	15-30
Magnesium alloy	—	100-200	100-200
Thermoplastics / composites	—	40-100	—

GUNDRILL

Feed Rate by Diameter (mm/rev)

Gundrill feed rates by material and bore diameter. For intermediate diameters, interpolate linearly.

Material	D=3mm	D=5mm	D=10mm	D=20mm	D=30mm
Low-carbon steel	0.005-0.010	0.010-0.020	0.020-0.040	0.050-0.080	0.100-0.160
Alloy steel (annealed)	0.005-0.010	0.010-0.020	0.020-0.040	0.050-0.080	0.100-0.140
Alloy steel (hardened)	0.004-0.008	0.008-0.018	0.015-0.030	0.040-0.070	0.080-0.120
Stainless steel	0.004-0.008	0.008-0.015	0.020-0.030	0.050-0.070	0.100-0.150
Cast iron	0.006-0.012	0.012-0.025	0.030-0.050	0.070-0.120	0.150-0.220
Aluminum alloy	0.020-0.040	0.040-0.080	0.070-0.130	0.150-0.280	0.300-0.500
Copper alloy / brass	0.015-0.030	0.030-0.060	0.050-0.100	0.100-0.200	0.200-0.400
Titanium alloy	0.003-0.006	0.006-0.012	0.010-0.025	0.030-0.060	0.060-0.100
Nickel superalloy	0.002-0.005	0.005-0.010	0.008-0.020	0.020-0.050	0.040-0.080

BTA

BTA Feed Rate (mm/rev)

BTA feeds are typically 3–10× higher than gundrilling for the same diameter and material.

Material	D=20mm	D=50mm	D=100mm
Low-carbon steel	0.08-0.18	0.20-0.40	0.30-0.60
Alloy steel (annealed)	0.06-0.15	0.15-0.35	0.25-0.50
Alloy steel (hardened)	0.05-0.12	0.12-0.28	0.20-0.40
Stainless steel	0.05-0.12	0.12-0.30	0.20-0.45
Aluminum alloy	0.15-0.30	0.30-0.60	0.50-0.90
Cast iron	0.10-0.25	0.25-0.50	0.40-0.75
Titanium alloy	0.03-0.08	0.08-0.18	0.12-0.28

CORRECTION FACTORS

L/D Depth Correction

As depth increases, reduce both speed and feed. Find your L/D ratio, apply the factors to your base Vc and feed.

L/D	3D	5D	8D	10D	15D	20D	30D	50D	75D	100D
Speed K_lv	1.00	0.85	0.70	0.60	0.50	0.40	0.35	0.28	0.22	0.18
Feed K_lf	1.00	0.80	0.60	0.50	0.40	0.35	0.30	0.25	0.20	0.16

💡 How to use: Base Vc × K_lv = adjusted Vc. Base feed × K_lf = adjusted feed. For L/D values between table entries, interpolate linearly.

EXAMPLE

Worked Calculation

Gundrilling 4140 alloy steel (annealed), 15mm dia × 450mm deep (L/D=30:1).

Base Vc:70 m/min (mid-range for alloy steel)

Base feed:0.030 mm/rev (interpolated for 15mm)

K_lv at L/D=30:0.35 → Adjusted Vc = 70 × 0.35 = 24.5 m/min

K_lf at L/D=30:0.30 → Adjusted feed = 0.030 × 0.30 = 0.009 mm/rev

Spindle:n = 24.5 × 1000 / (π × 15) = 520 RPM

Feed rate:Vf = 520 × 0.009 = 4.7 mm/min

Time:T = 450 / 4.7 = 96 minutes per hole

COOLANT PRESSURE

Pressure & Flow by Method

Method	Pressure (bar)	Notes
Gundrilling (D < 10mm)	80–150	High pressure, low flow; the small V-groove needs intense flushing
Gundrilling (D 10–40mm)	50–120	Pressure drops as diameter grows
BTA / STS	15–100	High flow, moderate pressure
Ejector (DTS)	10–50	High flow, moderate pressure — Venturi effect driven by flow, not pressure

💡 Flow, not just pressure: verify flow reaches the tool tip. A gauge at the pump does not prove the tip is wet — the ejector Venturi collapses below ~8 bar, and gundrill orifices clog if filtration drops below 20 μm.

BEST PRACTICE

Entry, Break-Through & Safety

💡 Entry: Start at 80% of target feed for the first 2–3mm of cut, then ramp to full feed.
Break-through: Reduce feed by 50% over the last 2–3mm to prevent exit burrs.
Retraction: Reduce speed to ≤50 RPM before retracting; keep coolant flowing to flush chips.

⚠️ Important: These are recommended starting values. Prioritize tool manufacturer recommendations. Start from lower limits for new materials. Monitor chip shape during the first 10–20 seconds of cut — it is the best real-time indicator of parameter suitability.

Feeds & Speeds Tables

Cutting Speed by Material

Feed Rate by Diameter (mm/rev)

BTA Feed Rate (mm/rev)

L/D Depth Correction

Calculations

Worked Calculation

Pressure & Flow by Method

Entry, Break-Through & Safety

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