Bogie Spring Cradles - In common with other key components, all sharp edges must be removed as they concentrate stresses in that area. The drawing states that we need a 1/16 of an inch radius. John and Geoff get to work. Once the top surface is finished, we will need to turn the cradle over so that the other surface can be addressed.
Small pedantic technical suggestion:
From an engineering standpoint, it is only internal corners which act as stress raisers. And (in the context of structural elements of a fullsize loco bogie) they need a radius much larger than 1/16".
The reasons for rounding off external corners include prevention of injury to humans or dings to the material, and 1/16" is sufficient for these purposes. A somewhat larger radius is more beneficial in these respects, and in particular helps the paint to avoid getting chipped, eroded or abraded, delaying corrosion getting behind the paint.