Short Answer:

Jigs are special tools used in manufacturing and fitting shops to hold the workpiece and guide the cutting tool, especially during drilling, reaming, or tapping. Jigs help in accurate and repeated machining without the need for marking or measuring each time.

There are different types of jigs based on the shape of the job, the operation required, and the method of support. Common types include plate jig, channel jig, box jig, template jig, and angular jig. Each type is designed for specific tasks to ensure precision, speed, and consistency in production.

Detailed Explanation:

Different types of jigs

In mechanical engineering, jigs are widely used in workshops and factories for guiding tools and holding parts during machining. They are especially useful in operations like drilling, tapping, or reaming, where accurate positioning of the tool is important.

Using a jig improves repeatability, accuracy, and speed in operations. Different types of jigs are designed based on the type of workpiece, the tool used, and the method of operation. Let us understand each type of jig in a simple and clear way.

1. Plate Jig

A plate jig is the simplest type of jig. It is a flat metal plate with one or more drill bushings to guide the drill.

Features:

• The workpiece is clamped under the plate
• Holes are drilled through bushings
• Best for flat workpieces

Used in: Drilling holes in small parts with simple shapes

Advantage: Easy to make and use

2. Channel Jig

A channel jig looks like a U-shaped metal block or channel. The workpiece is placed inside the channel and the drill is guided by bushings.

Features:

• Holds round or irregular parts securely
• Guides drill in fixed directions
• May include clamping devices

Used in: Machining of cylindrical rods, tubes, or shaped parts

Advantage: Provides support from three sides, ensuring stability

3. Box Jig (also called Box-type Jig)

A box jig is a strong jig shaped like a box that completely surrounds the workpiece. It supports and holds the job in a fixed position from all sides.

Features:

• Suitable for complex and heavy parts
• Can drill from multiple directions
• Contains bushings and clamps

Used in: Precision drilling of larger machine parts

Advantage: Very accurate and allows multiple holes in one setup

4. Template Jig

A template jig is a simple guiding plate placed directly on the workpiece, showing the position of the holes.

Features:

• No clamping mechanism
• Light and easy to use
• Used with soft or small jobs

Used in: Light drilling work with basic accuracy

Advantage: Quick and economical for low-volume jobs

5. Leaf Jig

A leaf jig has a hinged cover or leaf that can be opened and closed like a book. The top leaf holds the drill bushings.

Features:

• Easy to load and unload the part
• Provides firm clamping and guiding
• Can be locked during operation

Used in: Repetitive drilling of small-to-medium size parts

Advantage: Fast setup and user-friendly design

6. Angular Jig

An angular jig is used when holes need to be drilled at a certain angle instead of a straight line.

Features:

• Holds the workpiece at an angle
• Contains angled drill bushings
• May have adjustable guides

Used in: Angle drilling of brackets, flanges, or slanted components

Advantage: Ensures consistent angle in every job

7. Indexing Jig

An indexing jig is used when multiple holes need to be drilled at equal distances around a circle or on a face.

Features:

• Has a rotating mechanism
• Divides the part into equal steps
• Drill bushings guide the tool

Used in: Circular hole patterns like gears, wheels

Advantage: Ensures accurate spacing between holes

Conclusion

There are many types of jigs, each designed for specific operations and shapes of workpieces. Common types include plate, channel, box, template, leaf, angular, and indexing jigs. They help in guiding the tool accurately and holding the job securely. Using the right jig improves the speed, safety, and precision of the machining process, especially in repetitive production work.