HSS-G COBALT Premium Ground Jobber Drill Bits

These cobalt HSS ground jobber drill bits are built for the jobs where a standard HSS bit gives up. Made from M35 alloyed high speed steel with 5% cobalt content, they handle stainless steel, hardened alloys and other tough metals that would blunt a cheaper bit before you’ve broken through. If you’ve ever watched an ordinary drill bit turn blue and skate across a piece of 316 stainless, you’ll understand exactly why cobalt matters.

The key difference here is in the manufacturing process. These bits are fully ground from solid bar stock, rather than being rolled or milled. That gives a cleaner cutting edge, tighter dimensional accuracy, and a finish that holds up under sustained pressure. Manufactured to DIN 338, they meet the dimensional standard that most professional metalworking applications expect, so they’ll seat correctly in chucks and jigs without any wobble or runout issues.

Where Cobalt HSS Ground Jobber Drill Bits Earn Their Keep

The 5% cobalt content isn’t just a marketing number. Cobalt raises the heat tolerance of the steel significantly, which is the real reason these bits outperform standard HSS on hard materials. When you’re drilling stainless or alloy steels, friction builds up fast. A standard bit softens at the tip, loses its edge, and suddenly you’re generating more heat than you’re cutting. The cobalt in M35 keeps the cutting geometry intact at much higher temperatures, so the bit stays sharp for longer and cuts cleanly rather than just work-hardening the material.

Available in sizes from 1.0mm right up to 13.0mm, including some of the less common increments like 3.2mm, 4.2mm, 4.8mm and 6.8mm that come up more often than you’d think on fabrication and engineering work. That kind of range means you can keep the sizes you actually need on the van rather than improvising with whatever’s closest.

Single bits, packs of five, or packs of ten depending on what your workflow calls for. Good bits used properly will last, but having spares when you’re deep into a stainless steel job is never a bad idea.