Series 320: Machine Shop Practices

Course 315: Machine Shop Practice

Covers the principles of machining, measurement, tool grinding, and machine shop safety. Discusses the properties of metals, how to lay out and set up a job, how to use measuring devices such as the micrometer and vernier caliper, and how to read working drawings. Explains how to grind single-and multi-point tools.

Available Media: Interactive, Self-Study Textbook, Videos, Pre- and Post- Tests, Spanish Textbook

Lesson 1 - Principles of Machining

Topics:

Machine tools; Metal cutting tools; Properties of metals; Case hardening; Cutting metals; Cutting fluids; Speeds and feeds; Chip shape and disposal

Learning Objectives:

• Name the two main classes of machine tools.
• Tell how to identify ferrous and nonferrous metals.
• Explain methods of identifying steels.
• Define the following terms: tensile strength, compressive strength, ductility; and malleability.
• Explain various heat treating processes used with metals.
• List the functions of a cutting fluid.
• Explain how to change sfpm to rpm.
• Describe the information you can gather from chip color and shape.

Lesson 2 - Layout Work and Shop Safety

Topics:

Shop drawings; Scribing lines; Calipers; Measuring angles; Surface plates, gauge; Making a layout; Shop safety

Learning Objectives:

• Describe the tools commonly used for layout work in the machine shop.
• Explain the function of a surface plate.
• Define the terms bolt circle, pitch chord, and centerline.
• List the steps involved in laying out flange holes.
• Explain shop safety practices relating to eye protection, chip removal, and tool handling.

Lesson 3 - Setup Tools

Topics:

Holding devices; Supporting the workpiece; Rests; Step blocks; V-blocks; C-clamps; Angle plates; Hold-downs; Magnetic chucks; Safety

Learning Objectives:

• Explain how to hold and drive work held between centers on a lathe.
• Explain how to hold lathe work in a chuck, and how to mount and remove a chuck from a lathe.
• Define the term swing as it relates to a lathe.
• Tell how to hold oddly shaped workpieces on a lathe
• Explain when each of the following is used: collet chuck, steady rest, and follower rest.
• Explain how each of the following is used to hold work on a machine table: T-slot bolts and clamps, step blocks, V-blocks, C-clamps, angle plates, and planer jacks.
• Tell when and how to use a vise to hold a workpiece.
• List safety precautions for setup tools.

Lesson 4 - Setup Measurement

Topics:

Working drawings; Dimensions; Precision; Tolerance; Using a steel rule, micrometer, vernier caliper, sine-bar, and gauge blocks

Learning Objectives:

• Explain the importance of having a working drawing when machining a part.
• Define the terms section and sectional view.
• Name the three systems of dimensioning.
• Define the terms precision and tolerance.
• Define the term fit, and compare actual fit, clearance fit, interference fit, and transition fit.
• Name the simplest measuring tool in the shop.
• Explain how to hold and read a micrometer.
• Tell how to use a vernier caliper, sine-bar, and gauge blocks.

Lesson 5 - How to Grind Single-Point Tools

Topics:

Tool materials; Relief angles; Grinders and grinding wheels; Finishing, grooving, and threading tools; Carbide-tipped tools

Learning Objectives:

• Describe the various materials used for tools.
• Identify the parts of a single--point tool.
• List important specifications for single-point cutting tools.
• Name the two basic types of grinders and explain how they are used to sharpen single-point tools.
• Explain the standard marking system for grinding wheels.
• Describe the best way to grind carbide-tipped tools.

Lesson 6 - How to Grind Multi-Point Tools

Topics:

Grinding a drill; Checking lips and relief angles; Thinning the drill web; Milling cutters; Cutter relief, clearance, end mills, and counterbores

Learning Objectives:

• Describe the construction of a twist drill, including identification of its parts.
• Explain how to perform the following operations when grinding: check the drill lips, check the relief angles, and thin the drill web.
• List the three categories of milling cutters based on the way they are mounted on a milling machine.
• Name the most common type of milling cutter for maintenance work.
• Explain how to grind end mills, counterbores, and reamers.