Description Product Overview When you are rebuilding large engine blocks, boring deep hydraulic cylinders, or turning massive internal diameters on the lathe, standard bore gauges simply don’t have the reach. The Toyo Seiki 50-500mm Inside Micrometer Set is a premium, traditional Japanese metrology kit designed to measure massive internal spans with uncompromising accuracy. Massive 50-500mm Range: This kit is an absolute powerhouse of versatility. Using the precision micrometer head and the series of interchangeable extension rods, you can accurately measure any internal diameter from a compact 50mm all the way up to a massive 500mm (nearly 20 inches!). Tubular Extension System: The extension rods feature a rigid, lightweight tubular design. This is critical for large-diameter measurements, as it prevents the rods from sagging or flexing under their own weight when spanning wide bores, ensuring your reading is dead-accurate. Exceptional Japanese Precision: Before digital tools took over the shop floor, Japanese toolmakers relied on the flawless mechanical fit and finish of analog instruments. The thimble rotates with buttery smoothness, and the extension rods lock together with zero slop. Condition Used (Time Capsule Condition / Worn Wooden Box). Don’t judge a book by its cover! From the outside, the original wooden storage box shows its age, featuring the typical scuffs, scratches, and patina you would expect from a vintage shop tool. The “Time Capsule” Interior: Opening the weathered box reveals a true time capsule. The components inside are in absolutely exceptional, near-unused condition. The micrometer head, the extension rods, and the measuring faces present beautifully and are entirely free of rust or heavy wear. It is a gorgeous, fully functional piece of Japanese engineering that is ready to go back to work. Brand Information Toyo Seiki (Japan) is a storied name in Japanese precision engineering, highly respected for manufacturing industrial testing equipment and top-tier metrology tools. Much like vintage Mitutoyo or Starrett, old-school Toyo Seiki micrometers are heavily sought after by master machinists because they were built during an era where uncompromising mechanical quality was the absolute standard. Specifications FeatureSpecificationBrandToyo Seiki (Japan)TypeTubular Inside Micrometer SetMeasuring Range50mm – 500mmSystemMicrometer Head with Extension RodsIncludedMicrometer Head, Extension Rod Set, Wooden CaseConditionUsed / Pristine Interior (Weathered Box) Keywords Toyo Seiki, inside micrometer, 50-500mm micrometer, tubular bore micrometer, large inside micrometer, cylinder measuring tool, machinist measuring tools, vintage Japanese metrology, bore measuring tool.
