Vertical boring machine

A vertical boring machine is particularly adapted for holding and machining the large, heavy workpiece.
On vertical boring machine following work are done :

• Large gear blanks
• Locomotive and rolling stock tires
• Steam and water turbine castings
• Flywheels
• Large flanges and number of circular-shaped parts

A vertical boring machine can take an only a circular cut.

The vertical boring machine is of two types :

• Vertical turret lathe
• Standard vertical boring machine

Vertical boring machine parts :

1. Bed
2. Table
3. Housing
4. Crossrail
5. Tool-head assembly

Size of vertical boring machine :

Its size is specified by the diameter of its table or chuck expressed in mm.

The size of vertical turret lathe varies from 600 to 2000 mm. 

The size of a standard vertical boring machine is as high as 6000 mm.

Vertical boring machine tools :

The vertical boring machine tools are similar to lathe tools.

For boring operation, the clearance angle of the tool is greater than in turning or facing tool.

Vertical boring machine operation :

A vertical boring machine may generate a horizontal flat surface.

It can also produce cylindrical turned surface, bore internal hole, perform cutting off, necking or forming operation, and generate internal or external taper surface.

Jig boring machine

The jig boring machine is the most accurate in all type of boring machine. Jig boring machine first developed in the year 1910 in Switzerland. The real jig borer was first built in the year 1917 by Pratt and Whitney.

Jig boring machine is now used for the production of jigs, fixtures, tools and other precision parts which require a high degree of accuracy.
They have the highest accuracy through rigidity, low thermal expansion and measuring distance for accurately locating and spacing holes.

Jig boring machine is a metal cutting machine for finishing holes, planes and slots with a highly precise location of centres or surfaces without the use of special attachments for tool alignment.

In jig boring machine machining accuracy is very high within a range of 0.0025 mm. 

The spindle and other parts of the machine are extremely rigid to resist deflection and the vibration is minimum.
The spindle runs in preloaded antifriction bearings.
The jig boring machine requires temperature-controlled rooms for operation where temperature can be maintained constant.

Types of jig boring machine :

There are two types of jig boring machine :

1. Vertical milling machine type
2. Planer type

Methods of locating holes in the jig boring machine :

Accurate positioning is essential for producing accurate jigs, fixture, dies etc.

The most important operation in a jig boring machine is the accurate way of positioning a hole that can be done by one of the following methods :

1. Lead screw method
2. Mechanical and electrical gauging method
3. Optical measuring method

Jig boring machine operations :

• The jig boring machine primarily designed to produce precision dies, jigs and gauges.
• They also used as measuring machine to check up a job already manufactured in other machines.
• Also used in enlarging holes.
• Single point tools enables maximum accuracy in locating holes and give a better surface finish.
• Jig boring machine operated by highly skilled workers.

Multiple head type horizontal boring machine

Multiple head type horizontal boring machine resembles a double housing planer or a Plano-miller.

The table is supported on a long bed on which it reciprocates.

In there two vertical columns at two sides of the bed, nearly at the middle of the bed.

The two columns are bridged by a Crossrail.

This machine has two, three or four headstock.

This type of machine may be used as both a horizontal and vertical boring machine.

The machining operations can be performed simultaneously at different work surfaces.

Planer type horizontal boring machine

Planer type horizontal boring machine the table type but table slide directly on the bed instead of on a saddle and reciprocates at right angles to the spindle similar to a planer.

The end supporting column may be adjusted towards or away from the table for accommodating different widths of work.

This types of boring machine suitable for supporting a long work.

Floor type horizontal boring machine

The floor type horizontal boring machine having no table uses a stationary floor-plate on which T-slots are provided to hold the work.

The headstock supporting column and the end supporting column are mounted on the runways which are placed at right angles to the spindle axis.

Any crosswise adjustment or cross-feed movement is provided by the spindle itself and not by the work.

Table type horizontal boring machine

This is the most common type of all horizontal boring machines because the work is mounted on the table which is adjustable and feed is given by hand or power lengthwise or crosswise with respect to the bed of the machine.

The head stock may be adjusted vertically on the column and the spindle has a horizontal feed motion.

The machine consists of bed, head stock supporting column, end supporting column, head stock, saddle and table and boring bar.

This type of machine is suitable for general purpose work where other operations in addition to boring are required to be performed.

 

Horizontal boring machine

In a horizontal boring machine, the work is supported on a table which is stationary and the tool revolves in a horizontal axis.
A horizontal boring machine can perform boring, reaming, turning, threading, facing, milling, grooving and many other operations with suitable tools.
Different types of horizontal boring machines have been designed to suit different purposes.

Parts of Horizontal boring machine :

Bed :
The bed is fitted on the floor of the shop and has a box-like casting.
The bed supports the columns, tables and other parts of the machine.

Headstock supporting column :
The column provides supports to the headstock and guides it up and down accurately by the guideways provided on the face of the column.

End supporting column :
The end supporting column situated at the other end of the bed houses the bearing block for supporting a long boring bar.

Headstock :
The headstock mounted on the column supports, drives, and feed the tool.
The headstock may be moved up and down on the column for setting the tool for different heights of the work.

Saddle and table :
The table supports the work and provided with T-slots for clamping the work or for holding devices.
The saddle allows the work to be moved longitudinally on the bed.
The table may be moved crosswise on the saddle.

Boring bars :
The boring bar supports the cutter for boring operations on jobs having large bore diameters. 

Size of horizontal boring machine :

The size of that is specified by the diameter of its spindle in mm.
Spindle diameter varies from 75 to 355 mm.
Other important dimensions such as spindle motor horsepower, column heights, size of the table or size of the floor plate, spindle speed, feed and length of feeds, floor space required, the weight of the machine should be stated.

Boring machine mechanism :

The boring machine has different controls for movements of the different parts of the machine. A table type machine has movements mentioned below :

1. The headstock and the end supporting block may be moved up and down.
2. The spindle may be rotated with different speeds.
3. The spindle may be moved in or out by hand or power for feeding.
4. The saddle or table may be moved by hand pr power.
5. The columns may be moved by hand or power.

As all the controls are housed in a particular position of the machine the operator may give closed attention on the work while controlling the machine.

Work holding device for horizontal boring machine :

• Conventional work holding devices comprise of T-bolts and clamps, angle plates, step blocks etc.
• Special jigs are used in mass production work.

Horizontal boring machine operations :

In boring machine used for milling operation and the milling cutter may be fitted to the spindle. 

Facing cutter is used for machining flat vertical surfaces for face milling operation.

End mills are used to produce grooves and slots.

Other operations such as following below :

• Drilling 
• Reaming
• Counter boring
• Tapping
• Spot facing

Boring tool mountings for horizontal boring machine :

The different equipment for mounting cutters in horizontal boring machine are :

• Boring bar
• Boring head or cutter head
• Facing head

There are different boring tool used in boring bars are of different shapes and sizes for different types of operation.

Types of Boring Machine

The boring machine may be classified into four types. we can check it our below :

1. Horizontal boring machine 

• Table type
• Floor-type
• Planer type
• Multiple head type

2. Vertical boring machine

• Vertical turret lathe
• Standard vertical boring machine

3. Precision boring machine

4. Jig boring machine

• Vertical milling machine type
• Planer type

Boring machine introduction

The first boring machine tool was invented by John Wilkinson in 1775.

The boring machine is one of the most versatile machine tools used to bore holes in large and heavy parts such as engine frames, steam engine cylinders, machine housings etc which are practically impossible to hold and rotate in an engine lathe or a drilling machine.

By the use of the boring machine the range of speeds and feeds provided to various traversing components allow drilling, milling and facing operation with equal facility.

By the fitting of simple attachments, the use of the machine can be extended to include screw cutting, turning, planetary grinding or gear cutting.