{"product_id":"supra-mk-medium-natural-bristle-brushes-5-8-1-8-hole-pack-12","title":"Pack-12 Supra MK Medium 5\/8\" Natural Bristle Brushes-Unmounted With 1\/8\" Hole","description":"\u003cp\u003e\u003cstrong\u003eSupra MK 5\/8\" Medium Natural Bristle Brushes\u003c\/strong\u003e are premium unmounted miniature brushes designed for professional jewelers and metalsmiths who demand consistent, even performance on delicate finishing work. These brushes are \u003cstrong\u003emade in the USA\u003c\/strong\u003e with solid steel ring construction for exceptional durability and long service life.\u003c\/p\u003e\u003cp\u003eBrush filaments are made from natural animal hair and are permanently anchored in the solid steel ring, then uniformly distributed to ensure even wear across the bristle face. This construction makes them especially effective on flat, curved, small, and hard-to-reach surfaces where consistent contact is critical.\u003c\/p\u003e\u003cp\u003eSupra MK brushes are available in Soft, Medium, and Stiff formulations — this listing is for the \u003cstrong\u003eMedium\u003c\/strong\u003e bristle. Note that Supra does not manufacture an extra soft version; extra soft bristle brushes are produced in China and are a separate product entirely.\u003c\/p\u003e\u003cp\u003eThese brushes feature a \u003cstrong\u003e1\/8\" diameter center hole\u003c\/strong\u003e for use with hub adapters or screw mandrels fitted with the correct 1\/8\" diameter screws. Using a 3\/32\" diameter screw mandrel with this hole size will result in a loose, imprecise fit — use the appropriate 1\/8\" hardware for best results. Otto Frei also carries natural bristle brushes with 3\/32\" diameter holes if that shank size is preferred.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eSold by the dozen (pack of 12).\u003c\/strong\u003e\u003c\/p\u003e\u003ch3\u003eFeatures\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003ePremium natural animal hair bristles for professional finishing\u003c\/li\u003e\n\u003cli\u003eSolid steel ring construction for durability and consistent bristle retention\u003c\/li\u003e\n\u003cli\u003eFilaments permanently anchored and uniformly distributed for even wear\u003c\/li\u003e\n\u003cli\u003eEffective on flat, curved, small, and hard-to-reach surfaces\u003c\/li\u003e\n\u003cli\u003eMedium bristle stiffness for versatile polishing and finishing applications\u003c\/li\u003e\n\u003cli\u003e1\/8\" center hole compatible with appropriate hub adapters and screw mandrels\u003c\/li\u003e\n\u003cli\u003eMade in the USA\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eBrush Diameter\u003c\/th\u003e\n\u003ctd\u003e5\/8\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBristle Type\u003c\/th\u003e\n\u003ctd\u003eNatural animal hair\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBristle Stiffness\u003c\/th\u003e\n\u003ctd\u003eMedium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCenter Hole Diameter\u003c\/th\u003e\n\u003ctd\u003e1\/8\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eRing Construction\u003c\/th\u003e\n\u003ctd\u003eSolid steel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaximum Operating Speed\u003c\/th\u003e\n\u003ctd\u003e25,000 RPM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMount Type\u003c\/th\u003e\n\u003ctd\u003eUnmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCountry of Origin\u003c\/th\u003e\n\u003ctd\u003eUSA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSold As\u003c\/th\u003e\n\u003ctd\u003ePack of 12\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eNotes\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eCompatible hub adapters: 147.257 or 147.259 (sold separately).\u003c\/li\u003e\n\u003cli\u003eCompatible screw mandrels require 1\/8\" diameter screws: 143.160 or 143.162 (sold separately).\u003c\/li\u003e\n\u003cli\u003eDo not use with 3\/32\" diameter screw mandrels — the fit will be imprecise.\u003c\/li\u003e\n\u003cli\u003eNatural bristle brushes with 3\/32\" holes are available separately from Otto Frei.\u003c\/li\u003e\n\u003cli\u003eSupra does not manufacture extra soft bristle brushes; extra soft versions are produced in China.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Supra","offers":[{"title":"Default Title","offer_id":43584375062742,"sku":"116.648","price":21.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/9832\/0342\/files\/pack-12-supra-mk-medium-58-natural-bristle-brushes-unmounted-with-18-hole-otto-frei.jpg?v=1719956245","url":"https:\/\/www.ottofrei.com\/products\/supra-mk-medium-natural-bristle-brushes-5-8-1-8-hole-pack-12","provider":"Otto Frei","version":"1.0","type":"link"}