🔩 Drilling Operations

Drilling Calculators

Four calculators in one place: RPM and feed rate, thrust force and torque, cycle time, and tap drill size. Everything you need for a drilling job, no login, no nonsense.

Unit System
mm
Nominal drill diameter
m/min
From material / tool data
mm/rev
Typical: 0.05 – 0.35 mm/rev
Quick-fill: Recommended cutting speed (HSS drill)
Please fill in all three fields.
Spindle Speed (N)
RPM
⚙️
Feed Rate (Vf)
mm/min
Actual Cutting Speed
m/min
Feed per Rev
mm/rev
📐
Formula Used
📖 Formula Reference
Spindle Speed (N) N = (1000 × Vc) / (π × D)
Vc in m/min, D in mm
Feed Rate (Vf) Vf = N × f
f = feed per revolution (mm/rev)
Metric Note RPM rounds to nearest 10 on most machines. Always match to the available spindle speed.
Imperial (SFM) N = (12 × SFM) / (π × D)
D in inches, SFM = surface feet per minute
Unit System
mm
Nominal diameter of drill
mm/rev
Axial advance per spindle revolution
N/mm²
Material constant (Kc)
Quick-fill: Specific cutting force (Kc) by material
Please fill in all three fields.
Axial Thrust Force (F)
N
↕️
Drilling Torque (Md)
N·m
Cutting Power
kW
📐
Formula Used
📖 Formula Reference
Thrust Force (F) F = 0.5 × Kc × f × D
Kc = specific cutting force, f = feed/rev, D = diameter
Drilling Torque (Md) Md = (Kc × f × D²) / 8000
Result in N·m
Cutting Power (Pc) Pc = (Md × N × 2π) / 60000
N = spindle RPM. Add 20% for machine efficiency.
About Kc Specific cutting force varies with material, hardness, and chip thickness. Use preset values as starting points.
Unit System
mm
Total depth to drill (L)
RPM
Actual spindle speed on machine
mm/rev
Axial feed per spindle revolution
mm
Used to calculate approach distance
Multiply cycle time for batch
Depth, RPM and Feed per Rev are required.
Cycle Time per Hole
minutes
⏱️
Feed Rate
mm/min
Approach Dist.
mm
Total Holes
holes
Total Time
minutes
📐
Formula Used
📖 Formula Reference
Feed Rate Vf = N × f
N = RPM, f = feed/rev
Approach Distance A = D / (2 × tan 59°)
For standard 118° point angle: A ≈ 0.3 × D
Cycle Time T = (L + A) / Vf
L = hole depth, A = approach distance
Batch Time T_total = T × number of holes
This is machine cutting time only, not setup or tool change.
Select thread standard
Nominal thread diameter
%
Typical: 65–75% for most materials
Please select thread size.
Recommended Tap Drill
mm
🔧
Thread Size
nominal
Calculated Drill Dia.
mm
Thread Engagement
%
📐
Formula Used
Drill Size Calculated Dia. Clearance Best For
📖 Formula Reference
Tap Drill (Metric) d = D - p
D = nominal diameter, p = pitch (mm). 100% engagement.
With Engagement % d = D - (E% / 100) × p
E = 75% gives strong thread with less tap breakage risk.
Tap Drill (Inch) d = D - 1/TPI
TPI = threads per inch. For 75%: d = D - 0.75/TPI
Standard Drill Pick Always pick the nearest standard drill size equal to or slightly larger than the calculated value. Going smaller risks breaking the tap.
👨‍🔧
Vaibhav Dhokpande
Builder, TaskJunction

Why I built this calculator? Honestly, because I was tired of searching for these numbers mid-job and landing on pages that wanted me to sign up, download a PDF, or sit through an ad that auto-played at full volume.

Drilling sounds simple until you break a tap at 2 AM in a workshop with no replacement and no idea where you went wrong. Getting the drill size right, the feed right, the RPM right: these small things decide whether the job goes smoothly or you're calling the supplier in the morning.

Free tools for Indian engineers. Not freemium. Not "free for 7 days." Actually free, for everyone, forever. That's the whole point of TaskJunction.

Whether you're a diploma student doing your first workshop practical, a machinist at a small job shop, or someone prepping for competitive exams, you deserve the same quality tools as anyone else. No account needed. Works on your phone in the workshop.

If something is wrong in the calculations or you want a material added to the presets, just let me know. I'd rather fix it than have someone make a mistake because of a bad calculator.

Vaibhav
taskjunction.org