Quality Verification Views: 21

Simple ways to verify real cobalt HSS countersinks: 1) Check markings - quality products mark HSS-E, HSS-Co or 'cobalt high speed steel' on the shank or package; standard HSS only says HSS; 2) Check price - cobalt HSS is 30%-50% more expensive than standard HSS; suspiciously low prices are likely fake; 3) Spark test - grind on a bench grinder: cobalt HSS throws fewer, finer, straighter sparks with a darker red color; standard HSS throws more, coarser, branched bright-yellow sparks; 4) Hardness test - cobalt HSS measures HRC65-67, standard HSS HRC62-64; 5) Compare in use - on stainless steel, cobalt HSS lasts visibly longer with less wear and welding; 6) Check the manufacturer - reputable factories guarantee material and provide certificates; avoid unbranded products. The most reliable way is to ask the supplier for a material certificate (spectrum analysis report) or send it for testing yourself. All our cobalt HSS products carry a material guarantee - fake, ten times refund.