Activity Industry Sector

Activity Originally Created By: MaryRose Lovgren

Turning a brake drum

Part of Lesson Plan: **Turning Brake Drums (updated) By Eli Jaramillo

Activity Overview / Details

Materials needed:

  • Student worksheet:  "Turning a Brake Drum"
  • "Instructor Answer Key" version of the above worksheet
  • Four or more brake drums (Will be used by students for measuring)
  • Brake drum lathe
  • Four or more brake drum micrometers (Also to be used by students)
  • Four or more brake drum measuring calipers (Used by students)
  • 80-grit sandpaper
  • Safety glasses for all students

Instructor:  "Based on our checks, we have determined that the drum is OK to turn or resurface.  The first thing to be aware of is safety:  Eye protection is a must.  And you must not wear loose clothing.  Also, if you have hanging jewelry or long hair, it should be tied or secured out of the way."

Instructor:  "A few more 'rules of thumb' when turning brake drums:

  • Remove only enough material to take out imperfections and to provide a smooth surface.
  • Do not remove more than .060 inch over the standard drum diameter specification.
  • The amount of material removed during a single cut should be limited to .005 inch.
  • Do a final cut of .001"
  • After your final cut, use some # 80-grit sandpaper to give a final finish to your work.
  • "When turning the brake drum on one side of the vehicle, turn the brake drum on the other side to the same diameter."  

Instructor:  "Any questions on what we've covered so far?"

Instructor Note:   Use the Turning a brake drum worksheet Instructor Answer Key version as a guide when you demonstrate the brake lathe usage.  Students will follow along and fill in answers needed on their worksheets.

Instructor Note:  After demonstrating the brake lathe, have students work in groups to service a brake drum:  Or if you only have one brake lathe you may need to spread this activity out over a few lab days.  Either way, the students should be instructed to follow their worksheets which will guide them through the pre-checks, measurements, then through turning the drum if needed. And you'll be initialling the "Instructor Check-off' line on their worksheets when they've completed the exercise.  

For this activity, it's helpful to have some spare drums handy that the students can turn for practice in case their assigned drum meets specs.

Materials / Resource

  • Worksheet: Turning a brake drum Worksheet: Turning a brake drum [ Download ] Worksheet: Turning a brake drum