Taper – Methods of Expressing Taper, Standard Tapers and Taper Turning Methods

In the ITI Turner trade, taper turning is an important machining operation used to produce conical shapes on a workpiece. Tapers are widely used in engineering components such as shafts, tools, and machine parts. This chapter explains different methods of expressing tapers, standard tapers, taper turning methods, important dimensions, and taper turning using compound slide with calculations.

Introduction to Taper

A taper is a gradual reduction or increase in diameter along the length of a workpiece. It forms a conical surface.

Important Terms in Taper

• Large Diameter (D): Bigger end diameter
• Small Diameter (d): Smaller end diameter
• Length of Taper (L): Length over which taper exists
• Angle of Taper (α): Angle between axis and surface

Methods of Expressing Taper

1. Taper per Unit Length

Taper = (D – d) / L

2. Taper Angle

tan α = (D – d) / (2L)

3. Taper Ratio

Expressed as 1:n

4. Taper per Foot

Used in some standards (inch system)

Standard Tapers

• Morse Taper: Used in drills and machine tools
• Jarno Taper: Used in precision applications
• Brown & Sharpe Taper: Used in machine tools
• Metric Taper: Used in modern systems

Methods of Taper Turning

1. Form Tool Method

A specially shaped tool is used to produce taper.

2. Tailstock Offset Method

The tailstock is shifted to produce taper.

3. Compound Slide Method

The compound slide is swiveled to the required angle.

4. Taper Turning Attachment

A special attachment is used for accurate taper turning.

Taper Turning by Swiveling Compound Slide

Principle

The compound slide is swiveled at an angle equal to half the taper angle. The tool moves along the slide to produce the taper.

Calculation of Angle

tan α = (D – d) / (2L)

α = half taper angle

Example

D = 40 mm
d = 20 mm
L = 100 mm

tan α = (40 – 20) / (2 × 100) = 20 / 200 = 0.1

α = tan⁻¹(0.1) ≈ 5.71°

Set compound slide to 5.71°

Advantages of Compound Slide Method

• Simple method
• Suitable for short tapers
• No special attachment required

Limitations

• Not suitable for long tapers
• Manual feed required

Importance of Taper Turning

• Used in machine tools
• Ensures proper fitting of components
• Provides self-locking features

Precautions

• Set correct angle
• Check alignment
• Use proper cutting speed
• Ensure smooth feed

Application in Turner Workshop

In the Turner trade, taper turning is used to produce shafts, tool shanks, and machine parts. Proper understanding of taper calculations and methods ensures accurate machining.

The compound slide method is commonly used for small and precise tapers.

Conclusion

Taper turning is an essential machining operation in the ITI Turner trade. Understanding methods of expressing taper, standard tapers, and turning techniques is important for accuracy.

Proper calculation and setup ensure precise results.

In conclusion, mastering taper turning techniques is crucial for producing high-quality components in engineering workshops.