What Can Go Wrong With Back-Wall Echo Review in Machined Bearing Rings-

https://tank-scan-technology.summitquill.com/posts/what-to-check-about-scan-grid-design-for-machined-valve-bodies

What Can Go Wrong With Back-Wall Echo Review in Machined Bearing Rings? Precision rings have curved inner and outer surfaces. A back-wall echo can be a useful reference for sound transmission through a part