What is the minimum overlap of material required in a stress-carrying lap joint connecting two pieces of 1/4 inch flat bar?

In a stress-carrying lap joint connecting two pieces of 1/4 inch flat bar, the minimum overlap required is determined by the thickness of the materials being joined. For lap joints, standard practices suggest that the overlap should be at least four times the thickness of the thinner piece to ensure sufficient strength and load-bearing capability. Given that both pieces in this case are 1/4 inch thick, the calculation for minimum overlap would be:

Minimum Overlap = Thickness x 4 = 1/4 inch x 4 = 1 inch.

However, to account for variations in material properties, methods of welding, and safety factors, a more common industry guideline often rounds this number up. In practice, an overlap of 1-1/4 inches is typically recommended to ensure that the joint has adequate strength and to account for imperfections in fit-up and welding processes.

Thus, the correct answer is based on accepted engineering practices, which indicate a minimum of 1-1/4 inches of overlap for effective load distribution and to achieve the desired mechanical performance of the joint.