🔍 Key Concepts

• Set screw purpose – it is used to lock something on a shaft, not to clamp two pieces together • Hex head set screw shape – typically fully threaded, with no smooth (unthreaded) shank under the head • Difference between a bolt/cap screw and a set screw in standard fastener drawings

💭 Think About

• Look at figures C, D, G, and L: which one is drawn more like a bolt that passes through material rather than a short screw that bites into a shaft? • Which figure shows a length of smooth, unthreaded shank under the hex head, and how would that affect its ability to hold against a shaft? • If you needed the threads to contact the part being locked as close as possible to the head, which figures would work best, and which one would not?

✅ Before You Answer

• Identify which option has a plain (unthreaded) section between the head and the threads • Confirm that a proper hex head set screw should be fully threaded up to the head • Ask yourself: can this fastener’s threaded portion actually reach and grip the shaft or part if it is acting as a set screw?