Taper Turning Methods in Lathe Machine | 4 Basic Types of a Taper Turning Operation

Taper turning methods in lathe machine – An Introduction

A taper turning is the gradual reduction in diameter from one portion of a cylindrical workpiece into another portion as a machining process doing in a lathe machines. Tapers can be external or internal. If a workpiece is confined to the outside, there is an external taper; it has an internal taper if confined to the inside.

In conventional straight turning, the cutting tool travels along a line parallel to the axis of the workpiece, resulting in a completed product that has the same diameter throughout. When cutting a taper, on the other hand, the tool travels at an angle to the axis of the work, resulting in the production of a taper.

For turning a taper, the technique employed is determined by the factors such as degree of the taper, the length of the taper, its placement (internal or exterior), and the number of pieces to be turned.

Taper Turning Methods

There are five methods of Taper turning methods in lathe machine

1. Form tool method

2. Tailstock set over method

3. Compound rest method

4. Taper turning attachment method

5. Combining feeds method

It is critical that the cutting tool be precisely centered with respect to the axis of the workpiece when using any of these techniques; otherwise, the workpiece will not be properly conical, and also the rate of taper will fluctuate with each cut.

Form tool method, A Taper Turning Operation

This is one of the simplest taper turning methods in lathe machine to produce short taper. This method is shown in the above figure. To the required angle the form is grounded. The tool is fed perpendicular to the lathe axis, when the workpiece rotates.

Taper Turning By Form Tool Method - Taper Turning

The tool cutting edge length must be greater than the taper length. Since the entire cutting edge removes the metal, it will produce a lot of vibration and hence a large force is required. It is done in slow speed.

Tailstock set over method

Generally, when the angle of taper is very small this taper turning methods in lathe machine will be employed. The workpiece be placed in the live center. Now, the tailstock will be moved in a crosswise, that is perpendicular to the lathe axis by turning the set over method. This process is known as tailstock set over method.

Tailstock Set Over Method - Taper Turning Method

When it comes to offsetting the tailstock, one thing to consider is the length of the taper. When it comes to the taper, length is important. If the length of the taper varies, the offset will vary as well.

Formula to calculate the tail stock set-over method To calculate Off-set Height
01-Tailstock-Offset-Set-Over-Method-And-Formula-To-Calculate-The-Offset-Distance

01-Tailstock-Set-Over-Method-Tailstock-Offset-Centres
Tail-Stock Offset Centres

Hence here the job is inclined to the required angle. When the workpiece rotates the tool is moved parallel to the lathe axis. So that the taper will be generated on the workpiece.

Compound rest method

Tapering using a swivel compound slide will be the second most straightforward method of creating a taper after that. It can only be used on short tapers. On the compound slide, the angle that has been chosen is half that needed for the taper to be included. It is necessary to use caution in order to prevent bad ending.

Generally short and steep taper will be produced using this taper turning methods in lathe machine. In this method the workpiece will be held in the chuck and it will be rotated about the lathe axis. The compound rest is swiveled to the required angle and then it will be clamped in position.

Compound Rest Method - Taper Turning Methods In Lathe Machine

Then by using the compound rest hand wheel the tool will be fed. Both the internal and external taper can be done using this method. The important feature is that the compound rest can be swiveled up to 45° on both sides. Only with the help of the hand the tool should be moved.

Even while this technique may provide very accurate results, it has certain limitations owing to the absence of an automated feed and because the length of taper is limited by how far the slide can travel. It is possible to adjust the compound rest base to the necessary angle for taper turning since it is graded in degrees.

It is essential to know the included angle of the taper that will be machined in order to perform the operation. In the case of two crossing straight lines, an included angle is produced by and between them. The angle formed between the taper and the centerline is one-half of the included angle, and it is this angle that the compound rest will be adjusted for when it is assembled.

When using a lathe center with an included angle of 60, the swivel compound rest will be placed at a distance of 30 degrees from parallel to the centerline.

Taper turning attachment method

A Taper Turning Attachment may be used for longer tapers if the tapers are larger in length. In this taper turning methods on lathe machine by using bottom plate or bracket, a taper turning attachment is attached to the rear end of the bed. It has a guide bar which is usually pivoted as its center. The guide bar has the ability to swing and it can be set in any required angle. It has graduations in degrees.

On either side, the guide bar can be swivelled to a maximum angle of 10°. It has a guide block which connects to the rear end of the cross slide and it moves on the guide bar. The binder screw is removed, before connecting the cross slide, hence the cross slide is free from the cross slide screw.

Taper Turning Attachment Method - Taper Turning Method In Lathe Machine

Usually during taper turning gives shapes to the job will be held in the chucks or in the centers. To the required angle the guide bar turned.

Taper Turning Formula

The angle is calculated using the formula, tan (α/2) = (D-d)/2l or tan θ = (D-d)/2l

When the division is given in mm instead of degree, then the angular distance of the guide bar to be tilted is given by

Using the compound rest hand wheel the depth of cut will be given. At an half taper angle the guide will be set. Using this taper turning methods in lathe machine any taper turning method can be done.

01-Taper-Turning-Attachment-Method-Taper-Turning-Attachment-Formula-Taper-Turning-Attachment-Diagram

01-Taper-Turning-Attachment-For-External-Taper-And-Internal-Taper-Taper-Turning-Attachment-Diagram

Combining feeds Method

Another more advanced taper turning methodology is taper turning by combining feeds. Both longitudinal and cross feeds may be engaged concurrently in some lathes, allowing the tool to travel a diagonal course that is the product of the magnitude of the two feeds. The trajectory of the resultant can be adjusted by changing the feed rate by changing the gears given within the apron.

Taper Turning By Combining Feeds - Simultaneous Transverse And Longitudinal Feeds

FAQs

What is the meaning of taper turning?

Taper turning is a turning technique in which the cutting tool travels at an angle to the axis of the workpiece, resulting in a tapered form in the workpiece after the cutting tool has been moved. A tapered piece is one in which the diameter of the workpiece varies evenly from one end to the other while it is being turned. The workpiece may be tapered from either the interior or the exterior of the workpiece.

What are the different types of taper?

Taper is defined as a consistent variation in diameter that results in a wedge or conical shape. The three most popular techniques of taper turning on the lathe are: the offset tailstock method, the compound rest method, and the taper attachment method.

What are the limitations of the form tool taper turning method?

It is limited to cutting short tapers and requires knowledge of either the included angle or centerline angle.

Which of the following methods does not involve taper turning?

All of the five methods are examples of taper turning techniques. The compound rest technique, and also the taper attachment technique, may be used to turn both internal and external taper, while the tailstock offset method is only utilized for exterior tapers.

What is the meaning of tailstock set over?

It is common practice to use taper turning operation on lathe machine when the angle of taper is very small. It is necessary to put the workpiece in the live center. By rotating the set over technique, the tailstock will be moved in a transverse direction, which is perpendicular to the lathe axis, at this point.

Example Problem:

Calculate the tail stock set over for turning a taper on a job such that its two diameters are 80mm and 50mm. Total length of the job is 300mm and the length of tapered portion is 200mm only

Solution:

Taper angle, tan (α/2) = (D-d)/2l and another formulae to calculate offset distance is h = (L (D-d)) / (2*l)

= (300 (80 – 50) ) / (2*200) = 22.5 mm

What is the best way to specify a taper?

The taper is defined by the diameter of the workpiece throughout its length. The amount of taper defined by the ratio of the difference in the diameters of the taper to the length of the taper is known as the amount of taper. Examples of taper diameters are 1:4, or 0.5: 4 etc.

What is the meaning of taper in drawing?

A draft of a foundry pattern, as provided by the foundry.

What is the taper turning formula and how does it work?

The set over length may be calculated using the following formula: S=L*(D-d)/2l, where l denotes the taper length, L is the total job length, d denotes the smaller diameter, and D denotes the bigger diameter.

Which technique is utilized only for internal taper?

Swivelling the Compound Rest allows you to turn the taper. This technique is exclusively used for turning internal tapers, not for turning external tapers. Half cone angle (α) is used in this technique to swivel the compound rest, which means that it is rotated in a horizontal plane by half of the conical angle.

What is the formula for converting taper to degrees?

Divide the decimal inch by 12 to get the decimal foot taper per foot by dividing the decimal inch by 12. For example, 1.2/12 = 0.1 is a fraction. By calculating the arc tangent of the taper, you may convert the decimal foot taper to a degree angle in degrees. On calculators, the arc tangent is sometimes denoted by the symbols atan or tan-1.

Formula for the Taper Calculator. T = (dl – ds) / L.
Angle of taper in degrees = atan (0.5 x T)

Diameter that is larger (dl), Diameter is smaller (ds), and The length of a workpiece (L).

What is the best way to test a taper?

An instrument for measuring taper is taper ring gauge is employed.

Describe the method of generation of a long and small taper in a centre lathe?

1. Form tool method; 2. Tailstock set over method; 3. Compound rest method; 4. Taper turning attachment method are the four popular methods of generation to produce long and small taper turning in a centre lathe.

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