Drilling Horsepower Calculator

Inputs

Drill diameter (D)

Cutting diameter of the drill.

Spindle speed (n)

Drill rotational speed.

rpm

Feed per revolution (fn)

Axial advance for each spindle revolution.

Specific cutting force (kc)

Material/tool cutting-force coefficient. Use toolmaker data when available.

MPa

Machine efficiency (eta)

Allowance from cutting power to required spindle power.

Default result

Required spindle power(P_sp)

0.2356kW

Cutting power divided by the entered machine efficiency.

Also computed

Cutting power(P_c)0.1885kW

Spindle torque(T)1.875N·m

Material removal rate(Q)7.54cm³/min

Drilling feed rate(Vf)96mm/min

Cutting speed(Vc)37.7m/min

Efficiency used(eta)0.8

Method notes 3 notes

Drilling feed rate = feed per revolution * RPM.
Drilling MRR = pi * D^2 / 4 * feed rate.
Specific cutting force changes with material, drill geometry, web thickness, coating, wear, coolant and hole depth. Treat this as a spindle-load screen, then verify against tooling data and the machine load meter.