Review on 🪚 Metal JNBPRO Countersink Drill Bit by Dustin Miller

If you plan to use some countersinks just for rough work, they work fine for a while. I can't confirm the 5% cobalt claim, but assuming it's true they should hold up better than regular M2 HSS in harder steels. toothy, with the root of each tooth, a stress climber. So the line breaks off pretty quickly. This means fast matting of hard materials. The solution to the problem is a finer polishing of the edges, which unfortunately for most of us can only be done by the manufacturer. It's not something you'll be good at hand sanding. So if you're looking for a set of racquets that will probably work well with harder than mild steel for a while, this might work. Otherwise, buying a professional countersink will give you more mileage. Material is harder than mild steel.