{"product_id":"spi-21-988-1-test-indicator-ball-contact-point","title":"Spi 21-988-1 Test Indicator Ball Contact Point","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe SPI 21-988-1 is a ball-style contact point designed for use with dial test indicators requiring precise, repeatable surface contact. The hardened stainless steel ball tip measures 0.039 inches in diameter and the overall contact point length is 0.54 inches, making it suited for measuring in tight bores, grooves, and recessed features where a standard stylus cannot reach. This replacement contact point threads into compatible test indicator stems and is installed by metrology technicians, machinists, and quality control personnel working with precision measurement equipment in shop or laboratory environments.\u003c\/p\u003e\n\u003cp\u003eThis contact point is intended for applications where a small-radius ball tip is needed to probe fine features, undercuts, or contoured surfaces on machined parts. The stainless steel construction resists corrosion and wear during repeated contact cycles. It is a direct accessory for the SPI Integral Series test indicator line, providing an OEM-style replacement or supplemental tip for technicians expanding their measurement capability.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e0.039 inch ball diameter for probing fine features and small-radius geometry\u003c\/li\u003e\n  \u003cli\u003e0.54 inch contact point length suitable for recessed and hard-to-reach measurement surfaces\u003c\/li\u003e\n  \u003cli\u003eStainless steel construction for corrosion resistance and long service life\u003c\/li\u003e\n  \u003cli\u003eTip diameter of 0.039 inches matches ball diameter for consistent contact geometry\u003c\/li\u003e\n  \u003cli\u003eLightweight at 0.01 pounds — minimal added mass on indicator stem\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned for use with the SPI Integral Series test indicators. Verify thread size and stem compatibility before installation.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eContact point replacement on dial test indicators is performed by metrology or machine shop personnel. Before replacing the contact point, remove the indicator from any active measurement setup and secure the indicator body to prevent rotation damage to the spindle. Use the appropriate small wrench or contact point tool to thread the tip in by hand first, then snug gently — do not overtighten, as the threaded stem on test indicators is fine-pitch and easily damaged. Inspect the replacement tip for burrs or surface defects before returning the instrument to service.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBall Diameter\u003c\/strong\u003e: 0.039 inches (1.00 mm)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eContact Point Length\u003c\/strong\u003e: 0.54 inches (13.70 mm)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTip Diameter\u003c\/strong\u003e: 0.039 inches (1.00 mm)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eContact Point Material\u003c\/strong\u003e: Stainless Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Length\u003c\/strong\u003e: 0.75 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Width\u003c\/strong\u003e: 0.13 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Height\u003c\/strong\u003e: 0.13 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.01 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 1\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: SPI\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 21-988-1\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SPIROTHERM","offers":[{"title":"Default Title","offer_id":51707424538930,"sku":"21-988-1","price":17.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/b7b81ebd7aab10afe6dee6278a2adb67.jpg?v=1788440248","url":"https:\/\/voomisupply.com\/products\/spi-21-988-1-test-indicator-ball-contact-point","provider":"Voomi Supply","version":"1.0","type":"link"}