How do you set precise angles without a Sine Plate using the NBI Indexer?

Simple long-lasting indexing plates can be set to any angle very accurately.

  • Loosen the back side nut until the plastic plates are loose
  • Pull the seconds plate to the back of the fixture
  • Join the minutes plate teeth into the seconds plate teeth
  • Hold these 2 plates together and join the minutes plate into the teeth of the degree plate
  • Tighten the back side nut.
  • Twist the whole assembly of plates so the setting is at the edge of the datum bar.
  • Insert the wedge narrow end first.
  • The angle is now set

Angle Settings

NBI Angle Settings Guide

Shown above is a reading of:
42 degrees
11 minutes
6 seconds

NOTE: If setting minutes are greater than 30` you should be setting the angle to the next high setting.
Example: 30° 40`

You will see 91° exposed, because the indexing plates are closer to the position. Seconds plate will follow the same process as minutes plate.


  Maintenance instructions for Indexer