When it's time to replace the screws in a carbide insert holder, use the reference number on your holder to find the right size.

Clamp screws hold insert clamps at the proper height for tooling.

Lock pin screws hold the insert in place.

Fasten carbide inserts directly to these end mills for a hold that's strong enough to handle the high speeds of a CNC machine. Replaceable carbide-insert end mills reduce waste and cost in high-volume jobs—when the cutting edges dull, replace the carbide inserts instead of the entire tool. End mills have a square cut style for milling square slots, pockets, and edges. All are noncenter-cutting for operations where the sides of the teeth do most of the work, such as shoulder milling, contouring, and finishing. They cannot be used for plunge cuts.

Carbide inserts have a positive rake, which means the cutting edge is angled to reduce vibration and prevent thin workpieces from bending. All have chip breakers that prevent the creation of long chips, which can damage tooling and restrict the flow of coolant. Use uncoated inserts for general purpose milling and short production runs. Use aluminum-titanium-chromium-nitride (AlTiCrN) coated inserts for demanding, high-speed jobs in hard material. They’re harder and more wear resistant than uncoated carbide inserts.