Difference Between Slot Drill and End Mill

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Slot drills and end mills are both cutting tools used in milling operations, but they serve different purposes and have distinct design characteristics.

A slot drill typically has two flutes and is designed specifically for cutting slots. The cutting edges extend to the center of the tool, allowing it to plunge directly into material. This makes slot drills ideal for creating precise slots and pockets where the tool needs to start cutting from the center.

End mills, on the other hand, usually have more flutes （typically 3, 4, or more） and are designed for general milling operations. The cutting edges do not extend to the center, so they cannot plunge directly into material. End mills are better suited for peripheral milling, contouring, and side cutting operations where the tool approaches the material from the side.

The key differences include: slot drills can plunge cut while end mills cannot, slot drills have fewer flutes for better chip clearance in slot cutting, and end mills provide better surface finish for side milling operations due to more flutes and better stability.