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METAL CUTTING TOOLS: DEFINITION AND CLASSIFICATION

Today we are going to start a very important topic here with the help of this post i.e. metal cutting tools: definition and classification. 

So, let us first understand here the basics of metal cutting tool  


Metal cutting tool: Definition

Metal cutting tool is basically defined as a device used in metal cutting processes on machine tools for removing the layers of materials from the workpiece or blank in order to secure the product of specified size and shape with specified surface finish and accuracy.

Now we will see here the classification of metal cutting tools

Classification of metal cutting tools

The metal cutting tools are classified on the basis of number of cutting edges as mentioned below.

  1. Single point cutting tools
  2. Multi point cutting tools
  3. Forms tools

Single point cutting tools

A single point cutting tool will have an effective cutting edge and it will remove the excess materials from the workpiece along the cutting edge.

Single point cutting tools will be usually used on lathes, shapers, planers, etc. 

Single point cutting tools are classified as mentioned below 

  1. Forged tool
  2. Mechanically fastened tipped tool
  3. Brazed tipped tool
  4. Solid tool
  5. Tool bit inserted in the tool holder
  6. Right hand tool
  7. Left hand tool
  8. Round nose tool

Forged tool

Forged tools are manufactured from high speed steel or high carbon steel. The required shape of the tool is given by forging the end of a solid tool shank and further the cutting edges will be grounded to shape to provide the required tool angles.

Following figure displayed here indicates the forged tool.

Forged Tools

Mechanically fastened tipped tool

To ensure rigidity, tips are sometimes clamped at the end of a tool shank by means of a clamp and bolt as displayed here in following figure.

Mechanically fastened tipped tool


Brazed tipped tool

In brazed tipped type cutting tool, the cutting edge will be in the form a small tip made up of stellite and cemented carbide tool materials, which will be welded to the end of a carbon steel shank by brazing operation.

Brazed tipped tool is displayed here in following figure.

Brazed tipped tool


Solid tool

Solid tools are made up of high carbon steel, forged and ground to the required shape. They are directly mounted on the tool post of a lathe.

A lathe tool post is used to hold the metal cutting tool.

Tool bit inserted in the tool holder

In case of tool bit inserted in the tool holder, metal cutting tool will be inserted in a forged carbon steel tool holder and will be clamped in a position by bolt or screw as displayed here in following figure.

There are various advantages of tool bit over solid tool such as tool bit will be cheaper as compared to solid tool, regrinding of tool will be quite easy.

A tool bit will be easily withdrawn and replaced in position without disturbing the setting. 

Tool bit inserted in the tool holder

Right-hand tool and left-hand tool

A metal cutting tool will be said to be a right-hand tool or left-hand tool, if its cutting edge is on the right-hand side or left-hand side respectively when viewing the tool from the point end.

Multi point cutting tools

A multi-point cutting tool will have two or more than two cutting edges. For example, metal cutting tools used in the operation of drilling, milling and broaching will be considered as multi-point cutting tools.

In multi-point cutting tools, all the cutting edges may either operate one by one or engage simultaneously.

Each cutting edge of a multi-point cutting tool will be considered as a separate single point cutting tool with almost all the features of single point cutting tool.

Form tools

A form tool is basically a metal cutting tool which is shaped in such a way that it imparts a prespecified profile to the workpiece.

Form tools are usually ground on cutting tool elements as a replica of the work profile. These tools are used to shape short jobs for turret lathes.

Classification of form tools are displayed here in following table 

Classification of form tools

Therefore, we have seen here the basics of metal cutting tool i.e. definition of metal cutting tool and also the classification of metal cutting tools with the help of this post.

Now, we will be interested further to understand a very important concept in manufacturing process i.e. nomenclature of single point cutting tool with the help of our next post.  

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Reference:  

Production Engineering, By K C Jain and A. K. Chitale   

Image courtesy: Google     

Also read  

Positive and negative effects of friction 

Classifications of friction 

Coulomb's law of dry friction 

Some guidelines for solving frictional problems 

Concept of rolling resistance or rolling friction

Wedge friction and concept of self- locking 

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