The industry standard clearance hole sizes for a 3/8" fastener are typically slightly larger than the fastener itself, with sizes like 1/2" adhering to older standards and 5/8" reflecting more current recommendations, providing clearance for alignment and other tolerances.
The question concerns the appropriate clearance hole sizes for a 3/8" fastener in engineering practices. In mechanical engineering, a clearance hole is a hole that is slightly larger than the diameter of the fastener that will pass through it. This allows the bolt or screw to pass through without binding. The industry standard clearance hole sizes for a 3/8" fastener typically would be slightly larger than 3/8".
Taking into account the older "rule of thumb" of a clearance of 5 diameters side-to-side, this would suggest a hole size of approximately 1/2". However, with advancements and more precise engineering, a larger clearance of up to 8 diameters side-to-side might be recommended, suggesting a hole size closer to 5/8" or larger.
So, for a 3/8” fastener, an industry standard clearance hole size could be 1/2" based on the older guidelines, or larger such as 5/8", adhering to more current standards. These dimensions provide the necessary clearance for the fastener and account for variables such as expansion, alignment, and manufacturing tolerances.