What is the recommended cutting angle to be ground on a flat cold chisel?

The recommended cutting angle for a flat cold chisel is 70 degrees to 90 degrees. This range provides an optimal balance between durability and sharpness, allowing the chisel to effectively cut through materials such as metal without becoming dull too quickly.

In practice, a chisel sharpened to a lower angle (like in the 50 to 70-degree range) may become blunt faster due to the increased stress on the cutting edge, while a sharper angle (like 30 to 50 degrees) can weaken the edge and make it more prone to chipping or deforming under heavy use. Therefore, maintaining a cutting angle within the 70 to 90-degree range ensures that the edge remains robust while providing sufficient cutting action, making it suitable for a variety of applications in plumbing and metalworking.