How to Evaluate Displacements in a Rotating Flat Disk

The craft of woodworking is an exacting one, requiring careful measurements and precise tolerances. When building a complex object like a chair or desk, it is essential to ensure the pieces are the correct shape before you assemble them. Even items that are single pieces and mostly flat may require careful measurement. For example, a plate, wide bowl or similar item being made on a lathe is essentially a disk that needs to be checked for distortions or displacements at the bottom.

Things You'll Need

• Protective goggles
• Ear protection
• Wood lathe
• Pre-lathed disk
• Outside calipers

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Instructions

1. • 1

     Put on both eye and ear protection. With the disk still seated in the lathe from your previous shaping, turn the lathe on so the disk is spinning.

   • 2

     Open the outside calipers. Position the calipers so that one point is on the outside of the piece and the other point is on the inside.

   • 3

     Look at the caliper as the disk spins. Move it from the outer edge toward the center. If there is any displacement or widening of the calipers as you do this, the surface is not yet flat and requires more work with the tools to flatten the surface.