Washer stud

A stud that has a machined washer about mid-length that is used to join two resonators. This avoids bottoming the stud in its hole (thereby eliminating bottoming stresses) and assures good perpendicularity of the stud to its hole. There is anecdotal evidence that this may improve the performance of difficult horns —

See Scotto patent (figures 2 and 3) which describes such a device as prior art.

Washer stud for ultrasonic joint
Figure 1. Washer stud