TAHA Engineering Toolsby TAHA Knowledge Lab

Machining & Workshop

Taylor Tool Life Calculator

Tool life from cutting speed with V·Tⁿ = C, the speed for a target life, or n and C from two tests.

Inputs

Calculate from

From your own tool-life tests or the tool supplier for this tool and work material. It is always between 0 and 1.

Same unit as the cutting speed, with tool life in minutes.

Enter it to see how many parts one cutting edge should make.

Result

Tool life
24.3865
Working
T = (C ÷ V)^(1/n) = (400 ÷ 180)^(1/0.25) = 24.387 min

At this speed a cutting edge should last about 24.3865 min of cutting.

Educational estimate — check the assumptions below.

About this calculator

F. W. Taylor found that tool life falls sharply as cutting speed rises, following V · Tⁿ = C. Small changes in speed have a large effect: with n = 0.25, a 20% higher speed roughly halves tool life. The equation is used to choose a cutting speed for a planned tool-change interval, to compare tool grades, and in machining-cost calculations.

The constants n and C belong to one combination of tool, work material, feed, depth of cut and wear criterion. Find them from two tool-life tests (third mode), or use values from your tool supplier. None are built in.

Formula

V × Tn = C

T = (C ÷ V)1/n    V = C ÷ Tn    n = ln(V1 ÷ V2) ÷ ln(T2 ÷ T1)

V = cutting speed, T = tool life in minutes of cutting, n = Taylor exponent (0 < n < 1), C = cutting speed that would give 1 minute of tool life.

Worked example

  • n = 0.25, C = 400 m/min, cutting at 180 m/min: T = (400 ÷ 180)4 = 24.4 min.
  • Same tool, target life 15 min: V = 400 ÷ 150.25 = 203.3 m/min.
  • Tests: 200 m/min lasted 10 min, 150 m/min lasted 40 min → n = ln(200/150) ÷ ln(40/10) = 0.2075, C = 200 × 100.2075 = 322.5 m/min.

Assumptions and limitations

  • Valid only for the tool, work material, feed, depth of cut, coolant and wear criterion for which n and C were found. The extended Taylor equation (with feed and depth terms) is not used.
  • Tool life is cutting time only, judged by a wear criterion (for example a flank-wear land of a set width). Real tool life scatters widely; plan tool changes with a safety margin.
  • The equation is an empirical fit and is unreliable far outside the tested speed range.

References

  • F. W. Taylor, “On the Art of Cutting Metals”, Trans. ASME, 1907.
  • ISO 3685: Tool-life testing with single-point turning tools (test conditions and wear criteria).