{"product_id":"hss-counterbore-end-mill-m3-m20-pilot","title":"Counterbore End Mill - HSS 4 Flute Pilot Counterbore for Socket Head Cap Screws, M3 to M20","description":"\u003cp\u003eThis \u003cstrong\u003ecounterbore end mill\u003c\/strong\u003e cuts a flat-bottom counterbore around an existing hole so socket head cap screws sit flush with or below the surface. The fixed pilot rides in the drilled hole and keeps the cut centered.\u003c\/p\u003e\n\u003cp\u003eDrill the clearance hole first, then run the counterbore at low speed in a drill press, milling machine or CNC center. Each size is matched to a metric cap screw from M3 to M20.\u003c\/p\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eType: 4 flute pilot counterbore, high-speed steel (HSS)\u003c\/li\u003e\n\u003cli\u003eSizes (pilot x cutter): M3 3.2 x 6.5mm, M4 4.2 x 8mm, M5 5.2 x 9.5mm, M6 6.2 x 11mm, M8 8.2 x 14mm, M10 10.3 x 17.5mm, M12 12.4 x 20mm\u003c\/li\u003e\n\u003cli\u003eLarge sizes: M14 14.4 x 24mm, M16 16.5 x 26mm, M18 18.5 x 28mm, M20 21 x 30mm\u003c\/li\u003e\n\u003cli\u003eOverall length: 45-110mm depending on size\u003c\/li\u003e\n\u003cli\u003eWorkpiece materials: copper, aluminum, tool steel, cast iron, plastics and wood\u003c\/li\u003e\n\u003cli\u003ePackage: 1 counterbore in the size you select\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eBest for\u003c\/h3\u003e\n\u003cp\u003eFixture plates, jigs, machine guards and enclosures where cap screw heads must sit below the surface.\u003c\/p\u003e\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat size counterbore for an M6 cap screw?\u003c\/strong\u003e\u003cbr\u003eChoose the M6 size: 6.2mm pilot for the clearance hole and an 11mm cutter for the screw head.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use a counterbore in a hand drill?\u003c\/strong\u003e\u003cbr\u003eIt works best in a drill press or mill, where the spindle stays square to the part and the floor of the counterbore comes out flat.\u003c\/p\u003e","brand":"Belvik Tools","offers":[{"title":"M12 - 12.4mm Pilot x 20mm Cutter","offer_id":50638955970625,"sku":"200007763:201441035;200182270:100016941#12.4x20x12x40x20x83","price":24.99,"currency_code":"USD","in_stock":true},{"title":"M10 - 10.3mm Pilot x 17.5mm Cutter","offer_id":50638956003393,"sku":"200007763:201441035;200182270:100016940#10.3x17.5x12x8x18x74","price":20.99,"currency_code":"USD","in_stock":true},{"title":"M8 - 8.2mm Pilot x 14mm Cutter","offer_id":50638956036161,"sku":"200007763:201441035;200182270:100016939#8.2x14x12x8x16x67","price":17.99,"currency_code":"USD","in_stock":true},{"title":"M6 - 6.2mm Pilot x 11mm Cutter","offer_id":50638956068929,"sku":"200007763:201441035;200182270:172#6.2x11x10x6x16x58","price":15.99,"currency_code":"USD","in_stock":true},{"title":"M20 - 21mm Pilot x 30mm Cutter","offer_id":50638956101697,"sku":"200007763:201441035;200182270:100016945#21x30x16x21x26x110","price":80.99,"currency_code":"USD","in_stock":true},{"title":"M18 - 18.5mm Pilot x 28mm Cutter","offer_id":50638956134465,"sku":"200007763:201441035;200182270:100016944#18.5x28x16x18x24x100","price":76.99,"currency_code":"USD","in_stock":true},{"title":"M16 - 16.5mm Pilot x 26mm Cutter","offer_id":50638956167233,"sku":"200007763:201441035;200182270:100016943#16.5x26x12x16x22x100","price":65.99,"currency_code":"USD","in_stock":true},{"title":"M14 - 14.4mm Pilot x 24mm Cutter","offer_id":50638956200001,"sku":"200007763:201441035;200182270:100016942#14.4x24x12x12x20x90","price":58.99,"currency_code":"USD","in_stock":true},{"title":"M5 - 5.2mm Pilot x 9.5mm Cutter","offer_id":50638956232769,"sku":"200007763:201441035;200182270:168#5.2x9.5x8x6x13x51","price":13.99,"currency_code":"USD","in_stock":true},{"title":"M4 - 4.2mm Pilot x 8mm Cutter","offer_id":50638956265537,"sku":"200007763:201441035;200182270:167#4.2x8x6x5x10x45","price":12.99,"currency_code":"USD","in_stock":true},{"title":"M3 - 3.2mm Pilot x 6.5mm Cutter","offer_id":50638956298305,"sku":"200007763:201441035;200182270:166#3.2x6.5x9x4x7x45","price":11.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0735\/2801\/6961\/files\/S2f386868c9a04e0baf14c7d56caafc8cK.webp?v=1792628892","url":"https:\/\/belviktools.com\/products\/hss-counterbore-end-mill-m3-m20-pilot","provider":"Belvik Tools","version":"1.0","type":"link"}