{"product_id":"starrett-67678-inside-micrometer-4-inch-range","title":"Starrett 67678 Inside Micrometer 4 Inch Range","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe STARRETT 67678 is a mechanical inside micrometer designed for precise internal bore and hole measurements in demanding shop and field environments. It covers a measurement range up to 4 inches with a graduation of 0.0003 inches and an accuracy of 0.0002 inches, making it suitable for work where tight tolerances matter. The micrometer uses a ratchet stop thimble for consistent, repeatable gaging pressure and features three self-centering contacts with solid carbide measuring faces for durability and wear resistance. This tool is used by machinists, toolmakers, metrology technicians, and precision trades professionals.\u003c\/p\u003e\n\u003cp\u003eThe 67678 is appropriate for measuring internal diameters in bores, cylinders, housings, and similar features in manufacturing, maintenance, and inspection applications. The three-contact design with self-centering contacts ensures true readings without operator-induced tilt error. The maximum extension rod length of 6 inches provides reach flexibility for deeper bores. A setting ring with a 3.25-inch diameter is included for calibration. The tool ships complete with a case, contacts, instructions, setting ring, and wrenches, making it ready for immediate use in a shop or field setting.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eMeasurement range up to 4 inches with 0.0003-inch graduation and 0.0002-inch accuracy\u003c\/li\u003e\n  \u003cli\u003eRatchet stop thimble provides consistent gaging pressure for repeatable readings\u003c\/li\u003e\n  \u003cli\u003eThree self-centering contacts eliminate tilt error for true internal measurements\u003c\/li\u003e\n  \u003cli\u003eSolid carbide measuring faces resist wear in high-use environments\u003c\/li\u003e\n  \u003cli\u003eMaximum extension rod length of 6 inches accommodates deeper bore reach\u003c\/li\u003e\n  \u003cli\u003eIncludes case, contacts, setting ring, wrenches, and instructions for complete out-of-box readiness\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned for use as a standalone inside micrometer in bore and internal diameter measurement applications. Compatible with standard extension rod accessories up to 6 inches maximum length.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eThis instrument is used by machinists, toolmakers, and precision measurement technicians. Before use, zero and calibrate the micrometer against the included setting ring following the manufacturer instructions. Ensure the workpiece and micrometer are at thermal equilibrium before taking measurements to avoid thermal expansion errors. Handle measuring faces with care and store in the provided case to protect carbide contacts from damage.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMicrometer Type\u003c\/strong\u003e: Inside\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Measurement\u003c\/strong\u003e: 4 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGraduation\u003c\/strong\u003e: 0.0003 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAccuracy\u003c\/strong\u003e: 0.0002 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eResolution (Inch)\u003c\/strong\u003e: 0.00025 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMinimum Measurement\u003c\/strong\u003e: 80.00 mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThimble Type\u003c\/strong\u003e: Ratchet Stop\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRod Type\u003c\/strong\u003e: Ratchet\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Contact Points\u003c\/strong\u003e: 3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMeasuring Face Material\u003c\/strong\u003e: Solid Carbide\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Extension Rod Length\u003c\/strong\u003e: 6 inches (152.40 mm)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSetting Ring Diameter\u003c\/strong\u003e: 3.25 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Setting Rings Included\u003c\/strong\u003e: 1\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 6.9 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: STARRETT\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 67678\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"STARRETT","offers":[{"title":"Default Title","offer_id":51544217452850,"sku":"67678","price":2639.61,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/2801d4dba4e845333dffebdd4e2a42d3.jpg?v=1785925783","url":"https:\/\/voomisupply.com\/products\/starrett-67678-inside-micrometer-4-inch-range","provider":"Voomi Supply","version":"1.0","type":"link"}