PTI 25pc HSS Cobalt Drill Set. This 25-piece HSS Cobalt drill set is engineered for high heat-resistance and exceptional performance, making it ideal for drilling hard steels and stainless steel. Cobalt-Alloyed : High heat-resistance for drilling steels with tensile strength over 800 N/mm², including high alloyed steels, bearing steels, and both hot and cold rolled steel.
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