These sets include multiple high-speed steel square end mills in various sizes. Square end mills have a square nose and are rotated against a piece of stock to create flat-bottomed grooves with 90° inside corners. They are used for counterboring, side and face milling, and milling square shoulders. High-speed steel square end mills offer good wear resistance for basic milling applications. They're more flexible and can absorb more shock and vibration than carbide end mills.

These sets include multiple carbide square end mills in various sizes. Square end mills have a square nose and are rotated against a piece of stock to create flat-bottomed grooves with 90° inside corners. They are used for counterboring, side and face milling, and milling square shoulders. Carbide end mills provide excellent wear resistance, heat resistance, and hardness.