How to use the tool life calculator
A small increase in cutting speed costs a surprisingly large amount of tool life. Taylor captured that relationship as V × Tn = C, and this tool uses it to predict life at a given speed and to work out the cutting speed that actually produces parts at the lowest total cost.
The exponent n describes how sensitive a tool material is to speed. High speed steel sits at 0.125, so life collapses as soon as you push it, while ceramic and CBN sit between 0.45 and 0.55 and tolerate far more. The constant C is the speed that would give exactly one minute of life. Coated carbide at n 0.25 and C 1,300 SFM run at 650 SFM gives about 16 minutes of life.
Economic tool life is T = (1/n − 1) × (tool change time + tool cost ÷ machine rate per minute), and the speed matching that life is the minimum cost speed. Running faster shifts cost into tooling; running slower shifts it into machine hours. Because n and C depend on the exact tool and workpiece pairing, treat the listed values as starting points and confirm them with trial cuts.
Frequently asked questions
Flank wear land reaching 0.3 mm is the usual criterion. On precision work the limit is normally set earlier, at the point where size drifts or surface finish starts to degrade.
The basic Taylor equation treats speed as the only variable. Feed and depth do affect life, but far less than speed does, so they are usually left out unless you are using an extended form of the equation.