How to use this calculator
- Enter drill diameter. Use the drill cutting diameter.
- Enter RPM and feed per rev. Use the spindle speed and toolmaker feed recommendation.
- Enter full-depth requirement. Use the depth that must be at full diameter.
- Set point angle. Use the included drill point angle for the drill geometry.
- Read time and MRR. Use feed time and material removal rate for cycle planning.
How it works
Drilling feed rate is the axial feed per spindle revolution multiplied by RPM:
Vf = fn x n
Cutting speed is Vc = pi x D x n, with the diameter in metres.
For a sharp conical point, the extra depth from tip to full diameter is
Lp = (D/2) / tan(A/2). Material removal rate is the hole area
times feed rate: Q = (pi x D^2 / 4) x Vf.
Worked example
Verified against the live calculator
A 10 mm drill at 1200 rpm and 0.08 mm/rev
feed advances at 96 mm/min.
A 118° point adds 3.00 mm to a 25 mm
full-depth hole, so feed time is 28.00 / 96 = 0.292 min per hole.
Drilling 12 holes takes about 3.50 min of cutting feed time.
Frequently asked questions
How do you calculate drilling feed rate?
Drilling feed rate is feed per revolution times spindle speed: Vf = fn * n. For example, 0.08 mm/rev at 1200 rpm gives 96 mm/min.
How do you calculate drill point allowance?
For a conical drill point, point length is Lp = (D/2) / tan(A/2), where D is drill diameter and A is the included point angle.
How do you calculate drilling cycle time?
Cutting time is programmed drilling depth divided by feed rate. This calculator adds drill point allowance to full-diameter depth before calculating time.
How do you calculate drilling MRR?
Material removal rate is hole area times feed rate: Q = (pi*D^2/4) * Vf.
Does this include peck drilling time?
No. It is cutting feed time only. Add rapids, retracts, dwell, chip clearing, tool changes and handling separately.
Should I use 118 or 135 degrees?
Use the actual drill point angle. A 135 degree split point has a shorter point allowance than a standard 118 degree point.
Method & assumptions
- Feed time only; machine rapids, retracts, pecks, dwell and tool changes are excluded.
- Point allowance assumes a sharp conical drill point.
- MRR uses the full drill area and feed rate.
- Tool life, torque, thrust, coolant, chip evacuation and workholding rigidity are separate checks.