I see the biggest and best advantage of coated carbides is SPEED. Carbide is the hardest, most durable material for cutting. If your tool breaks down it wasn't the coating that failed it was your application. I.E. chip load ,speeds,feed,deep of cut. Carbide will break down faster if used in a convential cutting appliacation. Carbide is brittle if used in a interrupted cut manner. Carbide cuts best under full load.Also it is the best for climb cutting, which is the fastest cut because it is a compressive force cutter. That's why lathe inserts are all ways carbide. The coatings are just for lubricity and to keep the material from welding to the tool. If you are looking to work in your small shop and have low volume work, then HSS will be less expensive and readily resharpened for you. Coated carbides are for high volume, high speed,high feed applications. If you were to use a coated insert on that lathe finish you were looking for, you could get a glass finish by really cranking up the speed and boosting up the feed. In a nutshell, carbide for really high speeds and feeds. Way out lasts and out performs any HSS  |