Taylor’s tool life equation, Modified equation – Explained

Before discussing Taylor’s equation for tool life, and modified Taylor’s tool life equation, let’s discuss in brief about the tool life.

What is Tool Life?

Tool life is the actual working period of fresh cutting tool which gives satisfactory work & after that it needs to resharpen or replace.

Hence, it is a period from when the fresh tool starts work till it needs to replace or resharpen.

The tool life can be expressed in different ways as below,

  • Working period in minutes.
  • Number of jobs machined.
  • Volume of material removal.
  • Total length of cutting.

The life of the tool depends on a various factor. Some of them are as follows:- cutting velocity (VC), depth of cut (t), feed rate (So).

Out of these factors, cutting velocity affects the tool life to higher extent.

Taylor’s equation for tool life:

When factors like depth of cut, feed rate are not considered, then Taylor’s equation for tool life based on cutting velocity is written as,


V = Cutting velocity (VC)
T = Time in minutes
n = Tool life exponent

The following graph shows the relation between cutting velocity (VC) & rate of tool wear.

Graph for tool velocity, tool life, and tool wear

When the cutting velocity is less, the tool wear is slower, which leads to higher tool life.

And as cutting velocity increases the rate of tool wear increase which results in lower tool life.

Modified Taylor’s equation for tool life:

In Taylor’s tool life equation, only cutting velocity is considered to find tool life. But in actual feed rate (So), depth of cut (t) also affect the tool life.

By considering all affecting factor, the modified Taylor’s equation for tool life is written as,

`T=\frac{C_{T}}{V_{c}^{x}times S_{o}^{y}times t^{z}}`

T = Tool life in minute
Vc = Cutting velocity
So = Feed rate
t = Depth of cut

Where terms CT, x, y, z are depended on tool & job material which can found in machining data handbook. 

Read also:

Pratik is a Graduated Mechanical engineer. He enjoys sharing the engineering knowledge learned by him with people.

Leave a Comment