DML Exam 2 Part 1 Questions And Answers 2022/2023

Define the term pitch diameter - Answer - diameter in between the major and minor diameter Name two ways to measure a thread - Answer - Thread micrometer or three-wire thread measurement method. What is the rule of thumb for the length of internal thread to maximize the strength of the bolt? - Answer - As much as the screw diameter; a better assembly will result when 1.5 times the screw diameter is used Describe when class two fits are used. - Answer - Most screws, nuts, and bolts used in the manufacturing industry Describe UNC and UNF - Answer - Unified National Coarse thread series and Unified National Fine thread series What is the formula for calculating the OD of a machine screw? - Answer - D= number of the machine screw*0.013in + 0.060in what are set screws used for? - Answer - To secure gears or pulleys to shafts When are stud bolts used? - Answer - Stud bolts can be used instead of long bolts. Stud bolts are used to aid in the assembly of heavy parts by acting as guide pins. Describe the strength classification system and marking for bolts. - Answer - Strength grades of bolts are identified by markings on the heads. The grade indicates the strength of the fastener. A manufacturer's chart may be used as a guide for the proper torque of fasteners Explain two reasons why flat washers are used. - Answer - Flat washers provide a larger contact area than nuts and screw heads to distribute the clamping pressure over a larger area. What is the purpose of a helical spring lock washer? - Answer - It prevents the unplanned loosening of nut and bolt or screw assemblies When is an internal-external lock washer used? - Answer - On oversized holes or to provide a large bearing surface When are dowel pins used? - Answer - Used to achieve accurate alignment between two or more parts