In manufacturing and workshop practice, a fixture is best defined as which type of device used during production or inspection of a workpiece?

Introduction / Context:
In production engineering and workshop practice, jigs and fixtures are special workholding devices that improve accuracy, speed, and safety. Although the words are sometimes used together, they have distinct meanings. A fixture is primarily a device that holds and locates a workpiece during machining or inspection, while a jig not only holds the work but also guides the cutting tool. This question tests whether you can correctly recall the formal definition of a fixture and distinguish it from gauges and jigs.

Given Data / Assumptions:
• The term defined is fixture, not jig or gauge. • The options describe devices for checking accuracy, holding and locating work, and guiding tools. • We assume standard definitions from machine tool practice. • Holding, locating, guiding, and checking are different functions.

Concept / Approach:
According to standard manufacturing definitions, a fixture is a device designed to hold and locate a workpiece in a fixed position during a manufacturing or inspection operation. It ensures that the workpiece is correctly positioned and firmly clamped so that the operation can be carried out accurately and repeatedly. A jig, on the other hand, usually also guides the cutting tool, such as a drill jig with drill bushes. Gauges and measuring fixtures may be used to check accuracy but often do not guide tools. Therefore, the correct definition for fixture is the one that emphasises holding and locating the workpiece without mentioning guidance of cutting tools as an essential part.

Step-by-Step Solution:
Step 1: Recall that fixtures are workholding devices used on machine tools. Step 2: Note that their main functions are to locate the workpiece and hold it rigidly in the desired position. Step 3: Recognise that guiding the tool is the characteristic feature of a jig, not a general fixture. Step 4: Examine the options and identify which one mentions holding and locating during operations, without adding tool guidance as a necessary feature. Step 5: Option C describes a device that holds and locates a workpiece during inspection or manufacturing, which matches the formal definition of a fixture. Step 6: Therefore, option C is the correct answer.

Verification / Alternative check:
Machine tool textbooks often provide side by side definitions: a jig is a device that holds and locates a workpiece and also guides the cutting tool, whereas a fixture holds and locates the workpiece only. Inspection fixtures may be used to position work accurately for measurement, reinforcing that fixtures are about holding and locating. Devices that only check accuracy without holding work firmly are classified as gauges, not fixtures. This confirms that the more general holding locating definition in option C is the proper one for fixtures.

Why Other Options Are Wrong:
Option A describes a device used only to check accuracy, which is closer to the function of gauges and does not capture the main production role of fixtures. Option B describes both holding and locating the workpiece and guiding the cutting tool, which fits the definition of a jig rather than a fixture. Option D claims that all of the above are correct, but since options A and B represent different devices, this combined option is incorrect. Only option C accurately and specifically describes fixtures as workholding and locating devices used in operations and inspection.

Common Pitfalls:
Students often confuse jigs and fixtures because they are introduced together and sometimes used in combination. Another pitfall is to think that any device used near the workpiece is a fixture, without considering whether it guides the tool. Remembering the simple distinction jig guides the tool, fixture holds the work helps clarify their roles. Understanding these definitions also helps in reading manufacturing documents and in communicating clearly in engineering contexts.

Final Answer:
The correct choice is A device that holds and locates a workpiece during inspection or a manufacturing operation, because this description matches the standard definition of a fixture used in production engineering.