Slotter Machine: Parts, Types, Operations, Mechanism, and Working (With PDF)

A slotter machine is a production machine.

This is a very old type of the machine and was invented by BRUNEL.

The slotting machine is similar to a verticle shaper. The ram carrying the slotting tool reciprocates in a verticle guide-way of the machine.

The Slotting Machine can manufacture flat and contour surfaces, slots. and internal grooves.

Note: At the bottom of my article you will find the PDF downloadable link.

Slotter Machine Definition:

Slotter machine is defined as a machine tool uses for removing unwanted material chips from the workpiece to make splines, grooves and more. Here the Ram (Tool attached) moves reciprocating, whereas In shaper the ram moves horizontally.

This is a reciprocating type of Machine tool. (The Reciprocating type of Machine tools are Shaper, Planner and Slotter Machine).

We also called this machine is a vertical shaper machine.

It is known mostly for machining internal surfaces.

The tool we use in this is Single Point cutting Tool which is made up of High-Speed Steel.

Also Read: Types of Lathe Operations with Diagram

Schematic Diagram of Slotter Machine:

Schematic Diagram of slotting Machine

Slotter Machine Parts:

A slotter machine consists of these following parts:

  • Base
  • Column
  • Saddle
  • Cross-slide
  • Rotating or Circular table
  • Ram and tool head
  • Ram drive
  • Feed drive


It should be sufficiently rigid to take up the entire load of the machine.

It has to take all the load (dynamic and Impact loading) while operating.

The guideways perpendicular to the column face should be accurately finished to move the saddle easily and accurately.

Generally, it is made of Cast Iron.


The right vertical cast integral rigid part of the base is the column; it serves the following purposes:

  • It houses the driving mechanism of the ram, which reciprocates on its front vertical face.
  • It also houses the feeding mechanism of the table.
  • It moves on guideways on the base to provide a longitudinal feed of the table, i.e. in a perpendicular direction to the front vertical face of the column.
  • It also provides guideways on its top face, perpendicular to the guideways on the base for the cross-slide.
  • The longitudinal feed may be given either manually or by power.


It is mounted on the guideways of the saddle and can provide cross-feeding of the table.

  • It holds the circular table.
  • It provides the arrangement of cross-feeding either manually or by power.

Circular table or Rotating Table:

  • It can rotate on cross-slide to provide circular feeding of the work.
  • It can hold the work by clamping, using fixtures, fixing vice, etc.
  • It has the arrangement of rotary feeding either by hand or by power.

On some machines, the table may be graduated in degrees for indexing.

Ram and Tool Head:

Ram slides on the guideways mounted on the front vertical face of the column.

Ram provides a slot for changing the position of the stroke.

Ram carries the tool, which is mounted at the bottom – end of the tool head.

Ram Drive:

It provides the circular motion of the motor to the reciprocating motion of the ram in a vertical plane.

It also provides the arrangement of slower speed during the cutting or forward stroke and greater speed during the return stroke to reduce the idle time.

Feed Drive:

It provides the arrangement of longitudinal and cross–a feed of the table either by power or manual.

It also provides the arrangement of circular or rotary feeding of the table on a vertical axis.

Intermittent feeding of the table is supplied at the beginning of each cutting or forward stroke of the ram.

Kinematic System of Slotter Machine
Kinematic System of Slotter Machine

Slotter Machine Mechanism:

  • Hydraulic Drive (Greater speed Flexibility, Smoother operation, Stroke length can be adjusted )
  • Variable Speed Motor Drive (In this Multi-speed arrangement)

Hydraulic Drive:

A speed motor drives a hydraulic pump that delivers oil at a constant pressure to the line.

A regulating valve admits oil under pressure to each end on the piston alternately.

At the same time allowing oil from the opposite end of the piston to return to the reservoir.

The piston is pushed by the oil and being connected to ram by piston rod, pushes the ram carrying the tool.

The admission of oil to each end of the piston, alternately, is accomplished with the help of trip dogs and pilot valves.

As the ram moves and complete its stroke (Forward and Return) a trip dog will trip the pilot valve which operates the regulating valve.

The regulating valve will admit the oil to the other side of the piston and the motion of the ram will get reversed.

The length of the ram stroke will depend upon the position of trip dogs. The length of the ram stroke can be changed by unclamping and moving the trip dogs to the desired position.

Variable Speed Motor Drive:

In this type of slotter, speed is obtained by different gears present in the gearbox and the shaft rotates with the help of an electrical motor.

Basically it is used in modern large slotting machines.

Working Principle of Slotter Machine:

The working of the Slotter machine is similar to the shaper machine do but the main difference between them is the Shaper machine works horizontally whereas Slotter machines work vertically.

As we have studied all the parts in detail.

Now the ram is connected to the crank and crank connected to the gears. So what happened here is when we increase or decrease the gear speed, the rotation of crank increases and decreases. And as per these, the ram moves up and down.

We have attached the workpiece into the work table and manually we bring the ram near to the workpiece and according to the ram we adjust the worktable and then we have to clamp it.

Now we supply the power as per gear the crank rotates and the crank is connected to the ram so ram moves up and down.

During down (ram moves down) the cutting stroke takes place and while moving up or return stroke there is no cut.

If we have to cut at the different sections then manually we give feed to the work table and as per requirement, it cuts.

This is how it works.

Here I would like to add some more points on Work holding device in which work is attached or fixed.

  • T bolts and step block
  • Clamps
  • Vice
  • Parallel strips
  • Chuck
  • Special fixtures for holding
  • Adjustable block and more

Slotter Machine Operations:

It is used for various operations like:

  • Internal and external Flat surface Machining.
  • The internal recess of circular, semi-circular, concave and convex surfaces.
  • Internal and External Circular surfaces Machining.
  • Blind Holes Internal machining.
  • For shaping internal and external forms or profiles.
  • The machine operates vertical, Horizontal and at Some angle too (Inclined Surfaces).
  • Irregular surface machining.
  • Machining operation of Dies and Punches.
  • The operation like slots, grooves, splines, and keyways for both internal and external surfaces.
  • Internal and external gear teeth machining.
Machining Operations of a Slotter Machine
Machining Operations of a Slotter Machine

Some of the Important Terms to Remember:

The main factor for explaining these terms is: It explains how and what will be the rate of material to be removed?

Cutting speed :

The cutting speed is defined as the rate at which the work moves with respect to the tool.

This is expressed in RPM (Revolution per minute).

Depth of cut:

The depth of cut is defined as the distance measured between the machined surface and the un-machined surface is called depth of cut.

It is expressed in mm.

Feed :

The feed is defined as the distance the tool travels during 1 revolution of the parts.

These three terms give the details of surface finish, power requirements, and material removal rate.

Types of Slotter Machine:

Slotter Machines are can be categorized in these 4-types.

  • Punch Slotter
  • Precision Toolroom slotter
  • Production Slotter and
  • Special Purpose Slotter Machine

Let me give you a brief knowledge of these 4 types of Slotter Machine.

Punch Slotter:

This is a heavy and rigid type of machine.

This machine designed for the removal of a large amount of metal from forged or cast material.

The length of the puncher slotter is large it may be as long as 1800 to 2000 mm.

How does Punch Slotter work?

The ram is usually driven by a spiral pinion meshing with the rack teeth cut on the underside of ram.

The pinion is driven by a variable speed reversible electric motor similar to that of a planer machine.

The Feed is controlled by electrical gear.

Precision Toolroom Slotter:

The tool room slotter works with good machine speed and produces an accurate surface finish.

Precision Toolroom Slotter picture

Production Slotter:

This type of slotter is used for machining tapered jobs by ram swivel to 10 to 30 degrees.

Special Purpose Slotter Machine

This type of slotter machines offer a high volume of production at low cost, also it gives greater accuracy too.

Keyseater is one of the special purposes of slotter machines. It is used for machining keys on the wheel and gear hub.

Keyseater slotter picture

Slotter Machine Specification:

The specifications of a Slotter Machine is depended on the several factors some of these are:

  • Power Input
  • Type of drive
  • Maximum table drive
  • The maximum length of ram stroke
  • Number of speed
  • Number of feed
  • Table feed
  • Floor space required
  • The diameter of the Work Table in MM
  • kW of motor

Slotter Machine Application:

These are the applications of a Slotter Machine:

  • It is used for cutting Slots, Spline and Keyways, both internal and external.
  • It is also used for the Machining of internal and external gears.
  • Internal machining of blind holes.
  • It is used for light cuts.

Advantages of Slotter Machine:

The advantages of Slotter Machines are:

  • This is a light machine.
  • The tool uses here is a single-point cutting tool.
  • Low-cost machine.
  • Low Maintenance.
  • Accurate surface finish.
  • Machine efficiency is more.

Disadvantages of Slotter Machine:

The disadvantages of Slotter Machines are:

  • Rigid in construction.
  • Skilled worker requires to operate.

Let’s see a Keyway Slotting Operation:


  1. A slotting machine.
  2. Fixture and clamping screw for holding the job.
  3. Scriber or Marking Block
  4. Single point slotting tool.
  5. Slip gauge.


  1. Marking the keyway with the help of a scriber or marking block.
  2. Then clamping the workpiece with the help of fixture or clamps or you can use vice too.
  3. Clamp the keyway tool on the tool holder.
  4. Match the marking portion with the center of the tool.
  5. Define the length and position of the strokes.
  6. Start the machine and give feed gradually by hand.
  7. Measure the keyway with the help of a slip gauge.
  8. Continue the operation until the keyway is finished.
key-way slotting operation

Let’s see this video:

Differences between the Shaper Machine, Planner Machine, and Slotter Machine:

The tool reciprocates in a horizontal axis and job feeds in intermittent translatory motion.Job reciprocates in a horizontal axis and tool feeds in intermittent translatory motion.Tool reciprocates in verticle axis and job feeds in intermittent translatory motion.
Low machining accuracy.High machining accuracy.Low machining accuracy.
Power is very less.Power consumption is High.Same as a shaper, The rate of power consumption is low.
Lighter in construction and less rigid.Heavier in construction and more rigid.Lighter in construction but more rigid than verticle shaper.
Intended for small Jobs.This is intended for large Jobs.This is intended for small Jobs.
It Requires Less Floor Space.It Requires Large Floor Space.Whereas It Requires Less Floor Space.
In Shaper, The tool is moving and work is Stationary.The tool is Stationary and work is moving.Same as shaper, The tool is moving and work is Stationary.
Usually, only one tool is used on a shaper.Multiple tooling permits machining of more than one surface at a time.Only one tool is used for machining.
It can machine only one surface at a time.It can machine three surfaces at a time.Same as a shaper.
Cost of the machine less.Cost of the machine is high.Cost of the machine is little less than shaper.

Read Also: Shaper Machine: Parts, Types, Operation, and Quick Return Mechanism


What is the Slotter machine?

Slotter machine is defined as a machine tool uses for removing unwanted material chips from the workpiece to make splines, grooves and more. Here the Ram (Tool attached) moves reciprocating, whereas In shaper the ram moves horizontally.

How is a slotting machine specified?

A Slotter Machine can be specified as:
1. The maximum length of stroke of the ram.
2. The diameter of the table.
3. Maximum verticle adjustment of the ram.
4. Floor space required in a square meter.
5. The maximum longitudinal and cross travel of the table.

Which mechanism is used in a slotting machine?

1. Hydraulic Drive (Greater speed Flexibility, Smoother operation, Stroke length can be adjusted )
2. Variable Speed Motor Drive (In this Multi-speed arrangement)

what are the parts of a slotting machine?

A slotter machine consists of these following parts:
1. Base
2. Column
3. Saddle
4. Cross-slide
5. Rotating or Circular table
6. Ram and tool head
7. Ram drive
8. Feed drive

How many types of slotter machines are there?

Slotter Machines are can be categorized in these 4-types.
1. Punch Slotter
2. Precision Toolroom slotter
3. Production Slotter and
4. Special Purpose Slotter Machine


So far in this article, we already learned about Slotter Machine, and also we see the difference between Slotter, Planer, and Shaper machine.

Also if you like my article do share on your favorite social media and let me know in the comment section too.

If you have any doubts please post your question in our discussion board, I will try to solve your query as soon as possible.

And for PDF below is the download button.

Till then do check out our topics on Manufacturing Technology.


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Anup Kumar Dey

A Mechanical Engineer with 19 years of working experience in various renowned MNCs.

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