Carbide is a material made up of carbon and iron that is very hard and durable, making it ideal for machining, drilling or cutting. Many tools, including saw blades, lathe bits, drill bits, router bits and dental drilling tips are made of carbide in lieu of steel. Many times, steel tools will come covered with a carbide to provide it with extra strength and durability. Carbide comes in several different numbered grades--ranked from soft to hard. Each has its own unique properties that affect its ability to absorb shock, handle wear and tear, and withstand heat brought on by friction.
Carbide comes in four grades of durability--C1 to C17. Each grade has different degrees of resistance. Which grade you select will depend on its intended use or application, the material being drilled or cut, and your tolerance or preference for maintaining the carbide tools.
Resistance & wear
The lower carbon grades, like C1 or C2, are generally the softest, offering the least resistance when coming up against a metal object during use. For instance, a C1 blade that hits a hidden nail will likely not suffer any damage. However, frequent resharpening is required.
Lower grade carbon blades require more frequent sharpening and show wear and tear more frequently than higher carbon blades. For instance, a C4 blade will need much less sharpening. However, hitting a hidden nail will likely cause it to chip or break.
C2 is used for milling tools where friction temperatures do not exceed 400 degrees Celsius. Temperatures greater than this will cause carbide to decompose. C2 is commonly seen on non-cutting tools like punching or drawing tools where high heats are not generated. When dealing with metals like aluminum, a C2 carbide grade is used for roughing. When C2 is used in sawing, it is used to manufacture or coat steel rip blades.
C3 handles high heat resistance better than C2, and is often considered a universal coating material for almost any application. C3 is often used for dry machining as well as drilling and milling tools where friction temperatures are high. In milling C2 carbide is brought out for finishing after the C2 has completed the roughing process. For sawing purposes, C3 is frequently seen in crosscut or combination saw blades.
Carbide vs. steel
Carbide is an alternative material to steel for saws and other tool equipment. Carbide is 2 to 3 times more expensive than steel, but can last as much as 10 times longer without requiring re-sharpening. This is particularly true if a higher grade carbide is used.