B) Outside Diameter of Case Tube.
Outside Diameter of the Crown
Outside Diameter of the Case Tube
Using your Digital Caliper, measure the outside diameter of the case tube where the crown fits on. This measurement must be precise as it ensures a properly fitting crown and a water resistant seal.
Using your Digital Caliper, once again, measure the diameter of the threads located inside the crown on the stem.
As for mentioned, an important consideration to maintain is the original aesthetic appearance of the watch. These are some common shapes.