🔍 Key Concepts
• Understand common machine drawing symbols such as R, chamfer angles, and surface finishes
• Notice exactly where the 1/8"R is placed on the part in the illustration
• Distinguish between a radius/fillet, a chamfer (often marked with an angle like 45°), and a recess
💭 Think About
• Look for how other features are labeled in the drawing: how is the 45° feature called out, and how are straight distances shown?
• Ask yourself: when a number is followed by an angle symbol (°), what kind of feature is that, and when it is followed by an "R", what kind of feature is that?
• Check whether the callout 1/8"R is applied at an outside corner, an inside groove, or across a flat surface
✅ Before You Answer
• Verify that chamfers are usually dimensioned with an angle (like 45°) and a length, not just an R
• Confirm that surface finish or roughness is normally shown with special surface finish symbols, not just the letter R
• Check the drawing to see if the 1/8"R note is pointing to a rounded corner/edge on only one end of the tool, and not to both ends or to an internal recess