Prick Punch and Scriber in ITI Turner Trade

In the ITI Turner trade, marking tools are essential for accurate layout work before machining operations begin. Among the most commonly used marking tools are the prick punch and scriber. These tools help in transferring dimensions and marking precise lines on metal surfaces, ensuring accuracy in cutting and machining processes.

Introduction to Marking Tools

Marking tools are used to draw lines, points, and reference marks on workpieces. These marks guide machining operations such as cutting, drilling, and turning. Accuracy in marking is crucial because errors at this stage can lead to defective products.

The prick punch and scriber are simple yet highly important tools used in almost every workshop.

Scriber

A scriber is a hand tool used to mark fine lines on metal surfaces. It is made of high carbon steel and has a sharp pointed tip for scratching lines on the workpiece.

Material of Scriber

Scribers are made from high carbon steel or tool steel. The tip is hardened and tempered to maintain sharpness and durability.

Construction of Scriber

A scriber consists of a thin rod with one or both ends pointed. Some scribers have one straight point and one bent point for marking in difficult areas.

Types of Scribers

• Single Point Scriber: Has one pointed end.
• Double Ended Scriber: Has two pointed ends, one straight and one bent.
• Adjustable Scriber: Used in special applications with adjustable length.

Uses of Scriber

• Marking layout lines on metal surfaces
• Transferring dimensions from drawing to workpiece
• Marking reference lines for machining operations

Advantages of Scriber

• Produces fine and clear lines
• Easy to use
• Suitable for precise marking

Prick Punch

A prick punch is a marking tool used to make small indentations on a workpiece. These indentations serve as reference points for further operations such as drilling or marking.

Material of Prick Punch

Prick punches are made from high carbon steel. The tip is hardened to resist wear, while the body is tough to absorb hammer blows.

Construction of Prick Punch

A prick punch consists of a cylindrical body with a pointed tip. The tip angle is usually around 30° to 60°, making it suitable for fine marking.

Types of Punches

Although this chapter focuses on the prick punch, other types of punches are also used in workshops:

• Prick Punch: Used for light marking
• Centre Punch: Used for marking drilling points
• Dot Punch: Used for making deeper marks

Uses of Prick Punch

• Making small indentations along layout lines
• Marking points for drilling
• Providing reference marks for machining

Advantages of Prick Punch

• Ensures accurate marking
• Prevents slipping of drill bit
• Easy to handle

Difference Between Prick Punch and Centre Punch

Although both tools are used for marking, they have some differences:

• Prick punch has a sharper angle (30°–60°) for fine marking
• Centre punch has a larger angle (around 90°) for deeper marks
• Prick punch is used before centre punching

Marking Process Using Scriber and Prick Punch

The marking process involves the following steps:

• Clean the surface of the workpiece
• Apply marking medium (such as layout dye)
• Use a scriber to draw lines as per dimensions
• Use a prick punch to mark points along the lines

This process ensures that the layout is clearly visible and accurate for further machining operations.

Safety Precautions

While using scribers and prick punches, the following safety precautions should be followed:

• Handle scriber carefully to avoid injury from sharp tip
• Wear safety goggles while using punch
• Ensure punch head is not mushroomed
• Use proper hammer for striking punch

Maintenance of Tools

Proper maintenance increases the life of marking tools:

• Keep tools clean and dry
• Sharpen scriber tips regularly
• Grind punch tips when worn out
• Store tools properly after use

Application in Turner Workshop

In the Turner trade, scribers and prick punches are used for marking workpieces before machining. Accurate marking ensures proper alignment and dimension control during turning operations.

These tools are also used in fitting and assembly work to ensure proper positioning of components.

Conclusion

The prick punch and scriber are essential marking tools in the ITI Turner trade. They help in achieving accuracy and precision in layout work, which is the foundation of successful machining.

By understanding their materials, types, and uses, and by following proper safety practices, trainees can improve their skills and produce high-quality work.

In conclusion, mastering the use of marking tools like the prick punch and scriber is a key step in becoming a skilled Turner.