What is a customized workholding device called that is built for a specific part design in machining operations?

A customized workholding device specifically designed for a particular part design in machining operations is known as a fixture. Fixtures are used to securely hold and position the workpiece in the correct orientation to ensure precision during machining processes. They are tailored to fit the unique geometry of the part, allowing for consistent and repeatable machining operations, which contributes significantly to the overall accuracy and efficiency of the manufacturing process.

In contrast, jigs are typically used to guide the cutting tool rather than hold the workpiece, which differentiates them from fixtures. Clamps are more general securing devices that can hold parts but lack the precise design and specific orientation capabilities of fixtures. Vices are tools that can grip a workpiece but are not customized for specific designs in the way fixtures are; they offer more versatility rather than specialization for particular parts.