MFG 252 - Engine Lathe Theory II

1. Examine cutting 60-degree external threads on a lathe
   1. Describe the several 60-degree thread forms, noting their similarities and differences
   2. Calculate thread depth, in feeds, and minor diameters of threads
   3. Describe how the number of threads per inch can be checked
   4. Determine how fast a spindle should be turning for threading
   5. Explain the procedure for cutting left-hand threads
   6. Describe the procedure for picking up threads
2. Analyze cutting 60-degree internal threads on the lathe
   1. Calculate the minor diameter of the internal thread
   2. Explain the need for boring the minor diameter if the internal thread
   3. Explain the positioning of the thread cutting boring bar
   4. Determine the position of the compound rest for internal thread cutting
3. Examine cutting external Acme thread on a lathe
   1. Calculate thread depth and in feeds for Acme threads
   2. Demonstrate the ability to adequately grind an Acme threading tool
   3. Describe the procedure for roughing out course Acme threads
   4. Describe the procedure for finishing an Acme thread
4. Analyze Cutting internal Acme threads on the lathe
   1. Calculate the minor diameter of the internal Acme thread
   2. Explain the need for boring to the minor diameter
   3. Explain the positioning of the thread cutting boring bar
   4. Explain thread cutting internal Acme threads
   5. Describe how smaller internal Acme threads are tapped
5. Differentiate work support devices
   1. Identify the parts of a steady rest
   2. Explain the correct use of the follower rest
   3. Point out when a steady rest should be used
   4. Describe how a steady rest is set up on a straight finished shaft when it has centers in the ends
   5. Explain how a steady rest can be used on irregular surfaces such as square or hex stock