Are stove bolt and machine screw sizes designated by diameter, threads per inch, and length?

• A. False
• B. Diameter and length only
• C. Threads per inch only
• D. Diameter, threads per inch, and length

Answer: (D)

Sizes for stove bolts and machine screws are given by three measurements: diameter, threads per inch (the pitch), and length. The diameter tells you the overall size of the threaded portion so it will fit the hole or nut. The pitch, shown as threads per inch, determines how fine or coarse the thread is and how it will mate with a corresponding nut or tapped hole. The length specifies how far the screw will extend into the joint and how much thread engagement you’ll have. All three are needed to ensure a proper fit and secure fastening; without any one of them, the screw may not fit, may cross-thread, or may not reach the nut adequately.