"Countersinks softwoods and hardwoods like the world is ending tomorrow. First time I used it in softwood, I just about drilled a very large hole where I wanted a small countersink. It's just that sharp, and cuts so smoothly.
Haven't had occasion to use it in metal yet, so can't comment on that, and have only done a few dozen countersinks on various woods, hence the 3 stars for reliablity. However, it has already lasted longer than some cheaper alternatives."
"I bought this HSS countersink in preference to some cheaper alternatives because I've had experience with them and because this was made from High Speed Steel I knew it would last a while and take a decent edge when resharpened. Having now tried it I can confirm it produces a good clean cut without chatter, even in very soft wood and am very satisfied with the product."