PERFORMANCE GUIDELINES: APPENDICES

A4 Measuring Variation From the Specified Plane

To measure variation from the specified plane using a plane of reference:

  1. Place two blocks of equal thickness on either side of the surface you are considering.
  2. Stretch a string across the top of the blocks so the string does not sag; the blocks may have to be secured from moving.
  3. Measure the difference between the string and the actual surface and subtract the thickness of the blocks.

Compare the result with the allowable variation in the guidelines.