Adjusting External Bubble Levels

1. Tribrach Bubble Level Adjustment

1. Set up the RTS on Tripod
2. Use the Internal bubble level to 1:10 Scale
3. Compare the internal bubble level to the external bubble level on the tribrach
   1. If the bubbles match up, there is no need for adjustment
   2. If the bubbles are different then adjustments are needed to the external bubble level.
      
4. Under the bubble level there is 3 screws that are 2.5mm Hex.
   
5. Included with every Trimble instrument is a Tube with different size Hex keys
   
6. Use the correct sized Hex key to adjust the screws to match the External bubble level with the internal instrument bubble level.
   

2. Stedi- Rest Rod bubble level adjustment

To adjust the bubble level on rods, a Stedi-Rest is required. Included with every kit is a Stedi-Rest. The Stedi-Rest is required to adjust the bubble level on telescopic rods while out in the field.

A 2.5mm Hex Key is required to adjust the adjustment screws. Included with every instrument is a tube with different Hex keys inside.

1. Set up the Tripod
2. Attach the Stedi-Rest to the Tripod using the bell assembly screw
3. Place the rod into the Stedi-Rest
   
4. Adjust the Stedi-Rest until the level vial indicates plumb.
5. While observing the level vial, rotate the rod 180 degrees
   1. If the level bubble holds true in the circle, it's properly calibrated
   2. If the level bubble drifts out of the circle, adjustments are needed
      
6. To re-calibrate the level, rotate the rod to the position where the bubble is farthest from the middle of the circle.
7. Make 1/2 correction by adjusting the adjustment screws under the bubble level
   
8. Adjust the Stedi-Rest to remove the error
9. Rotate the rod 180 degrees, repeat the procedure until the bubble remains in the center of the circle.