======Brown & Sharpe No.621 Surface Gauge======
This is a Yellow Level Tool and is unlocked by Metal Shop Orientation

====General====
  * The surface gauge is typically used on the [[surface_plate|Surface Plate]] in conjunction with a [[indicators|Dial Test Indicator]]
  * It can be used to make relative height measurements using a reference (i.e., a gauge block), or perpendicularity measurements (using a cylinder square).
  * It can also be used to measure parallelism or flatness.