Objective
This activity introduces students to the process of shaping and finishing a machine key. Using a shaper machine, students will produce a straight key from tool steel. The key will then be finished and sized using a surface grinder. Students will also learn to round the key tips through precision grinding to achieve a proper fit inside the keyway.
Materials and Equipment
The following materials and tools are essential for successfully completing this activity. Ensure they are available, complete, and in proper working condition before starting.
- Tool Steel Blank (Key Stock)
- Shaper Machine
- Surface Grinder with Magnetic Chuck
- Vernier Caliper
- Bench Grinder or Abrasive Wheel
- Safety Goggles
- Ruler or Steel Rule
- Vise or Clamping Setup
Procedure
Initial Setup and Workholding
- Cut the tool steel blank slightly longer than the final key length to allow for finishing operations.
- Mount the blank securely in the shaper machine's vise, ensuring firm clamping.
- Align the blank so that one face lies flat and parallel to the ram stroke direction.
Shaping the Key Profile
- Set the shaper to an appropriate stroke length and feed rate.
- Begin shaping to flatten one face of the blank.
- Rotate the key $90\degg$ as needed and repeat the process to machine adjacent faces.
- Shape until the desired key thickness and width are nearly achieved.
- Use a vernier caliper to measure the dimensions after each pass to avoid overcutting.
Surface Grinding for Finishing
- Place the shaped key on the surface grinder's magnetic chuck.
- Lightly grind the faces to reach the specified final thickness and width, ensuring accuracy and squareness.
- Use fine passes to improve surface finish and dimensional tolerance.
Rounding the Ends
- Mark the required tip radius on both ends of the key.
- Carefully shape the rounded ends using a bench grinder or abrasive wheel.
- Ensure both ends are evenly rounded for a proper sliding fit into the keyway.
Final Inspection
- Clean the finished key and measure all critical dimensions using a vernier caliper.
- Test the key for fitment in both the shaft and flange keyways.
- Perform final deburring or adjustments if necessary.