How far from the mold line should the jaws of the brake be set back for a bend of 120* and a radius of 3/16 inch (0.1875) on 0.051-inch aluminum?

Setting the jaws of the brake back from the mold line is crucial to accurately achieve the desired bend angle and radius in sheet metal fabrication. For a bend of 120 degrees with a specific radius, there are mathematical formulas that determine how far the brake should be set back to ensure that the bend occurs correctly without causing excessive distortion or material failure.

In this situation, the correct distance of 0.413 inch is derived from taking into account the bend allowance, which is influenced by the material thickness, bend radius, and bend angle. The formula typically involves calculating the material's stretch, considering the inner radius of the bend, and factoring adjustments based on the sheet metal thickness.

By understanding that the distance from the mold line to the brake jaw has to account for the 120-degree bend and the 3/16 inch radius, the calculated value arrives at 0.413 inches. This specific setting ensures that as the brake operates, the material bends uniformly around the intended radius without causing the material at the outer edge to stretch too much or the inner edge to compress excessively.

This selection illustrates the importance of accurate measurement and application of specifications in metalworking processes to achieve high-quality results in component fabrication.