ASTM A108 covers cold-finished round steel, offering tighter dimensional tolerances (±0.001 inches for small diameters) and smoother surface finish than hot-rolled A29. Cold finishing (drawing or turning) increases strength (e.g., 1018 cold-finished: 440 MPa tensile vs. 370 MPa hot-rolled) via work hardening. A108 is used for precision parts (bearings, fasteners), while A29 is preferred for applications where machining removes surface layers (e.g., forging blanks). A108 also specifies stricter straightness (0.001 inches/ inch) for high-precision manufacturing.