The eLearning Center for Gatlin Education Services

Covers the use of the dividing head. Covers plain, differential, and angular indexing. Explains the use of the dividing head for milling hexagons. Proceeds to the cutting of spur gears, helical gears, and cams.

Lesson 1 - Using the Dividing Head

Topics:

Indexing; Dividing head; Indexing fractions of a turn and parts of a degree; Sector arms; Selecting an index plate; Angular and differential indexing

Learning Objectives:

• Describe indexing and its uses.
• Identify the parts of a dividing head.
• List the four types of indexing you can do with a dividing head.
• Explain how to use sector arms to index fractions of a turn.
• Select the right index plate for the job.

Lesson 2 - Dividing Head Setup

Topics:

Dividing head center, driver, and chuck; Milling hexagons; Side and straddle milling; Setting up the dividing head; Indexing the workpiece

Learning Objectives:

• Mount a dividing head on a milling machine table.
• Mount work between a dividing head and footstock.
• Mount work in a dividing head chuck.
• Index and side mill or straddle mill a hexagonal workpiece.
• Use the dividing head to index a series of holes in a circle.

Lesson 3 - Milling Spur Gears

Topics:

Milling spur gear teeth; Concentricity; Aligning the workpiece; Setting up the dividing head; Indexing with a rotary table; Gear tooth calipers; Helical milling; Helix angle and pitch

Learning Objectives:

• Index spur gear teeth on a gear blank.
• Use formulas to compute gear tooth dimensions.
• Select the correct cutter for specific spur gear tooth dimensions.
• Explain how to use a rotary table.
• Use the measuring over pins technique to check the dimensions of gears.
• Define the terms helix, helix lead, helix angle, and helix pitch.

Lesson 4 - Helical Milling

Topics:

Using idler gears; Milling helical flutes; Indexing; Selecting and aligning the cutter; Setting depth of cut; Milling a helical gear

Learning Objectives:

• Use change gears to vary the lead of the milling machine.
• Describe the purpose of idler gears.
• Compute the lead of a helix.
• Index and mill helical teeth on a cutter.
• Index and mill helical gears

Lesson 5 - Milling Cams

Topics:

Cam functions; Nonpositive and positive cam systems; Uniform motion, harmonic cam systems; Incremental-cut method

Learning Objectives:

• Describe positive and nonpositive cam systems.
• Define radial cam terms such as cam lobe, uniform rise, cam rise, and cam lead.
• Mill a uniform-rise cam.
• Mill a short-lead cam.
• Mill a multilobe cam.
• Explain how to use the incremental-cut method to mill a nonuniform rise cam.