If you have ever sent a 2D drawing to a machine shop and received a call asking, “How tight do you actually need this chamfer to be?” — you have experienced the gap between "design intent" and "manufacturing reality."
(Note: ′ = minutes of arc. 60′ = 1 degree.) iso 2768 angular tolerance
You have a 45° chamfer on a 15mm long edge, with "ISO 2768-m" (Medium). Look at the row for 10–50mm. The tolerance is ± 40′ (40 minutes) . That is roughly ±0.66°. A Common Design Mistake Mistake: Drawing a 90° corner on a 200mm bracket and writing "ISO 2768-f" (Fine). Reality: Fine class for a 200mm leg gives you roughly ±5′ (0.08°). That is incredibly tight. The machinist will need to set up the part on a sine plate or use a CMM to verify. Your "simple" bracket just became expensive. If you have ever sent a 2D drawing