Absolute level calibration

[Dirtlaw]

Because we deal with a projectile that travels through the atmosphere absolute level is a factor we must consider and absolute level is based on the Earth's gravitational field. Machinists don't face a problem as difficult as the one we face. Absolute level has troubled me a bit because I didn't know how to develop a standard to adjust my Starret machinist level to its maximum accuracy. Stupid me! Without a standard I would have to except the "as it comes" solution as a compromise. Here is an elegant solution:

https://www.youtube.com/watch?v=bWoqkfpZRkQ

[ar15barrels]

Flip the level around from end-to-end after you calibrate it on a level surface.
If the bubble is not in the same position in both directions, the level is not calibrated or the reference surface is not level.
It does not matter if the reference surface is not perfectly level as long as you can read how OFF level it is accurately with the graduations on the bubble and the graduations read the same in both directions you check the level.

[pacrat]

Flip the level around from end-to-end after you calibrate it on a level surface.
If the bubble is not in the same position in both directions, the level is not calibrated or the reference surface is not level.
It does not matter if the reference surface is not perfectly level as long as you can read how OFF level it is accurately with the graduations on the bubble and the graduations read the same in both directions you check the level.

^^^CORRECT RESPONSE^^^

[nedro]

Do you know how to get exact height around a corner and away from your standard?

[Dirtlaw]

^^^CORRECT RESPONSE^^^

Simple, but because of that still elegant. The quest for knowledge is one of life's greatest journeys. I praise God that I still have the opportunity to learn.