Metalworking Glossary "J"

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Telephone: 208-406-2515

J Is for Jig Grinder

Metalworking Glossary for the Letter J

See the index to the Glossaries here:

Jacobs Chuck. A common term for the modern drill chuck, it is so named because the original was invented in 1902 by Arthur Irving Jacobs. It was the first drill chuck with a toothed sleeve and key, and after patenting it, A. I. Jacobs founded what would later become The Jacobs Chuck Manufacturing Company. Off-brand chucks built after that design are usually called Jacobs-style chucks and often just Jacobs chucks for short, even though they aren’t built by the Jacobs company.
Jeweler’s Mill. Not a traditional milling machine, a jeweler’s mill uses a hardened steel roller to imprint a design into copper or another softer metal.
Jig. A device that holds a workpiece in a precise location and guides the tools that cut or otherwise work on it.
Jig Grinder. Used almost exclusively by tool and die makers to create jigs (templates used for accuracy in fabrication), as well as dies and fixtures.
Jo Block. Another name for a highly precise gauge block, a Jo block is used for making very accurate measurements. The name Jo block is short for a Johansson gauge block, named after its developer, the Swedish inventor Carl Edvard Johansson.