What is the included angle of a twist drill recommended for soft metals?

The included angle of a twist drill recommended for soft metals is typically 90 degrees. This angle is ideal for drilling soft materials because it provides a balance between cutting efficiency and preventing the drill from binding in the material. A 90-degree angle has a wider flute at the tip, allowing for effective chip removal and reducing the likelihood of the drill clogging in the softer metal.

When drilling through soft metals, this angle facilitates smoother cutting and helps maintain the integrity of the drill bit, minimizing wear that can occur with sharper angles. Softer materials are easier to penetrate with a wider angle, which also helps ensure that the drill remains centered during the operation, leading to cleaner holes.

In contrast, other included angles, such as 45 degrees and 60 degrees, are typically suited for harder materials, as they require more precise cutting and a sharper point to penetrate the material effectively. An included angle of 120 degrees is generally used for specialized applications and would not be appropriate for standard drilling in soft metals.