With flutes that lift chips out of the hole, you don't have to stop drilling to clear these bits manually. They improve coolant flow to dissipate heat and prevent clogs that can damage the bit and ruin the hole. High-speed steel is good for general purpose drilling in most metals.

With flutes that spiral in the opposite direction of other bits, these are primarily used to remove stripped screws. Choose a bit that’s slightly smaller than the diameter of the screw’s head. Set your power tool to rotate in reverse. Slowly drill in the center of the screw head, maintaining constant pressure. As the bit penetrates, it will catch onto the screw and reverse it out of the hole. If the screw is badly stripped, you might need to punch a starter hole. Also known as reverse-flute bits. High-speed steel is the versatile choice for drilling most metals.

Use these end mills for general purpose milling in most material, such as aluminum, brass, bronze, iron, and steel. They have a square end for milling square slots, pockets, and edges.

End mills with fewer flutes provide better chip clearance for high-volume, high-speed plunge, slotting, and roughing cuts; end mills with more flutes provide a finer finish and operate with less vibration when run at high speeds.

When one end wears out, switch to the opposite end for two times the life of a standard high-speed steel end mill. Made of high-speed steel, these end mills are for general purpose milling in most material, such as aluminum, brass, bronze, iron, and steel. Their square ends make them good for milling square slots, pockets, and edges. All are center cutting, allowing plunge cuts into a surface.

End mills with fewer flutes provide better chip clearance for high-volume, high-speed plunge, slotting, and roughing cuts; end mills with more flutes provide a finer finish and operate with less vibration when run at high speeds.