{"product_id":"robert-bosch-tool-group-bl21a-black-oxide-drill-bit-set-21pc","title":"Robert Bosch Tool Group BL21A Black Oxide Drill Bit Set 21pc","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe ROBERT BOSCH TOOL GROUP BL21A is a 21-piece black oxide drill bit set designed for general-purpose metal and material drilling applications. Each bit carries a black oxide coating that reduces friction during drilling, extending bit life in everyday use. The set includes a no-skate tip geometry for clean, accurate starts without center-punching, and bits sized 3\/16 inches and larger feature a three-flat shank for improved chuck grip and reduced slippage. Size markings are high-visibility and clearly stamped on each bit for fast identification on the job. This set is suited for professional tradespeople and general contractors who need a reliable multi-size bit assortment on hand.\u003c\/p\u003e\n\u003cp\u003eThe BL21A covers a wide range of common hole sizes from 1\/16 inch up to 1\/2 inch, making it practical for residential and light commercial work across HVAC, plumbing rough-in, electrical, and general carpentry tasks. The set includes 21 bits: two 1\/16 inch, two 5\/64 inch, one 3\/32 inch, one 7\/64 inch, two 1\/8 inch, one 9\/64 inch, one 5\/32 inch, one 11\/64 inch, two 3\/16 inch, one 13\/64 inch, one 7\/32 inch, one 15\/64 inch, two 1\/4 inch, one 5\/16 inch, one 3\/8 inch, and one 1\/2 inch bit. The assortment addresses the most frequently called-for drill sizes in trade work without requiring a specialty set.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eBlack oxide coating reduces friction and heat buildup during drilling\u003c\/li\u003e\n  \u003cli\u003eNo-skate tip design enables clean, accurate starts on metal and other materials\u003c\/li\u003e\n  \u003cli\u003eThree-flat shank on bits 3\/16 inches and larger prevents bit rotation in the chuck\u003c\/li\u003e\n  \u003cli\u003eHigh-visibility diameter markings allow quick size identification\u003c\/li\u003e\n  \u003cli\u003e21-piece assortment spans 1\/16 inch through 1\/2 inch for broad coverage\u003c\/li\u003e\n  \u003cli\u003eGeneral-purpose construction suitable for metal, wood, and plastic substrates\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as a general-purpose drill bit set compatible with standard 3-jaw keyed and keyless chucks on corded and cordless drills commonly used in trade applications.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eThese bits are installed and removed by a licensed or journeyman-level tradesperson using a standard drill with a compatible chuck. Ensure the drill is powered off and unplugged or the battery removed before changing bits. Seat the three-flat shank fully into the chuck and tighten securely before drilling to prevent slippage. Use appropriate cutting fluid when drilling ferrous metals to extend bit life.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePiece Count\u003c\/strong\u003e: 21\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCoating\u003c\/strong\u003e: Black Oxide\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Metal\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShank Type\u003c\/strong\u003e: Three-Flat\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSize Range\u003c\/strong\u003e: 1\/16 inch to 1\/2 inch\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication\u003c\/strong\u003e: General Purpose Universal Drilling\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 12 per case\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 19.68 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: ROBERT BOSCH TOOL GROUP\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: BL21A\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"BOSCH","offers":[{"title":"Default Title","offer_id":51560213807410,"sku":"BL21A","price":536.74,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/35c2def3c9a612010240f8a662530a14.jpg?v=1786449413","url":"https:\/\/voomisupply.com\/products\/robert-bosch-tool-group-bl21a-black-oxide-drill-bit-set-21pc","provider":"Voomi Supply","version":"1.0","type":"link"}