{"product_id":"spi-21-229-0-radius-contact-point-4-48-dial-indicator","title":"Spi 21-229-0 Radius Contact Point 4-48 Dial Indicator","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe SPI 21-229-0 is a radius-style contact point designed for use with dial indicators in precision measurement applications. Machined from black oxide steel, this contact point threads into AGD Group 1 dial indicators via a 4-48 thread and provides a 3\/8-inch contact length with a 3\/16-inch diameter tip. The radius profile delivers consistent, repeatable surface contact on curved, flat, or irregular workpiece surfaces. Machinists, quality control technicians, and metrology professionals install this type of accessory when replacing worn contact points or when converting a standard indicator to a radius-tip configuration for specific gauging tasks.\u003c\/p\u003e\u003cp\u003eThis contact point suits precision measurement setups in machine shops, manufacturing floors, and inspection environments. It is compatible with dial indicators conforming to AGD Group 1 specifications, which is the standard sizing group covering most common shop-grade and inspection-grade dial indicators. The 4-48 thread is the industry-standard thread for this indicator class, making field swaps straightforward without additional adapters.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eRadius contact point style for consistent surface contact on curved and flat workpieces\u003c\/li\u003e\n\u003cli\u003eBlack oxide steel construction for corrosion resistance and durability\u003c\/li\u003e\n\u003cli\u003e4-48 thread size matches AGD Group 1 dial indicator standards\u003c\/li\u003e\n\u003cli\u003e3\/8-inch contact length provides adequate reach for recessed measurement surfaces\u003c\/li\u003e\n\u003cli\u003e3\/16-inch tip diameter suits general-purpose indicator gauging tasks\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned for use with dial indicators conforming to the AGD Group 1 industry designation using a standard 4-48 contact point thread.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation requires no special tools beyond a small wrench or fingers to thread the contact point into the indicator stem. Remove the existing contact point by unthreading counterclockwise before installing the replacement. Avoid overtightening, which can damage the indicator stem threads or alter the gauge's zero calibration. Re-zero the indicator after any contact point change before taking measurements.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eContact Point Style\u003c\/strong\u003e: Radius\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePoint Material\u003c\/strong\u003e: Black Oxide Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Size\u003c\/strong\u003e: 4-48\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eContact Point Length\u003c\/strong\u003e: 3\/8 inches (0.3750 inches)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTip Diameter\u003c\/strong\u003e: 3\/16 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIndustry Designation\u003c\/strong\u003e: AGD Group 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.1 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 1\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\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: 21-229-0\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SPIROTHERM","offers":[{"title":"Default Title","offer_id":51703900307762,"sku":"21-229-0","price":14.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/1e917e84c1b66f0c9e8abc93b9ae7e21.jpg?v=1788419355","url":"https:\/\/voomisupply.com\/products\/spi-21-229-0-radius-contact-point-4-48-dial-indicator","provider":"Voomi Supply","version":"1.0","type":"link"}