CNC machining and lathe machining processes usually encompass the use of several different machining tools, types of fixtures, and some common types of jigs. When it comes to multidimensional machining operations, this means that tools can be used in a variety of different ways to achieve the desired results.

Out of the many tools used in machining, two of them are confused, and their naming terms are often used interchangeably. In this article, we’ll talk about jigs and fixtures and their differences.

What Is a Jig?

The jig is a work-holding device that’s mostly used to guide the motion of another tool, like cutting tools and drill bits. The main purpose of jigs is to increase interchangeability, simplify the manufacturing process, and assure higher accuracy and repeatability in the mass production process.

However, these aren’t the only advantages of jigs in mechanical engineering or woodworking. These tool guiding devices also grant less skill-intensive labor and reduced production costs in industries that rely on operations such as boring operations, reaming, counterboring, tapping. Here are some common types of jigs:

• Template jigs
• Plate drill jigs
• Angle plate jigs
• Channel jigs
• Box jigs
• Leaf jigs
• Other jigs used for drill bushing, slotting and guiding other tools

What Is a Fixture?

The fixture holds and supports the workpiece in the correct position, maintaining its desired orientation with respect to the machine and the cutting tools. The main purpose of a fixture is to ensure that all parts produced using the same fixture will maintain the same level of conformity and interchangeability.

They’re mostly used in specific operations, such as milling, planning, slotting, grinding, or shaping. There are several fixtures designs available:

• Plate fixture
• Angle plate fixture
• Vise-jaw fixture
• Indexing fixture
• Milling fixture (on milling machines)
• Profile fixture

Jig Vs. Fixture: What Is the Difference?

For people who are new to mechanical engineering, fastening or clamping workpieces to a machine table, jigs and fixtures may be very confusing. They’re both similar in their goal, as they promote productivity and efficiency, but they ultimately function differently. Here’s are the major differences between the two:

Function — A jig directs the cutter to work at a specific point on a workpiece. It also helps to support and locate the component. However, the fixture just secures, supports, and locates the workpiece. It does not direct the machine component.

• Complexity — Jigs are generally easier to use, as they require less preparation and less skill
• Weight — Fixtures tend to be heavier and sturdier, as they have to withstand stronger vibrations and cutting forces
• Fitting — Jigs can be hand-held or fixed to the machine table, but fixtures almost exclusively require clamping or fastening
• Contact — Fixtures are designed in a way in which they hold the workpiece and don’t come into any contact with any machining tools. On the other hand, jigs are specifically made to guide the machining tools, so they must come in contact with the tool to establish accurate machining parameters.

Summary

Though used as synonyms, jigs and fixtures are very different tools. Jigs are made to guide the cutting tool while the workpiece remains stationary, and fixtures are made to guide the workpiece while the machining tool remains in place.

If you want to learn more about jigs and fixtures, don’t hesitate to contact Reid Supply and check out their comprehensive library of practical guides and technical literature.