螺柱轴线
变幅杆和增幅杆（有时还有换能器）都带有一根螺柱，用于将其连接到相邻的谐振器。换能器通常有一根用于紧固压电陶瓷的叠堆螺栓。穿过这些螺柱轴线的轴线称为螺柱轴线。
对于圆柱形谐振器，螺柱轴线定义了谐振器的一条潜在对称轴。
在某些情况下，"螺柱轴线"也可称为"谐振器轴线"。
Stud axis
Horns and boosters (and sometimes transducers) have a stud which is used to attach them to the adjacent resonator. Transducers normally have a stack bolt that secures the piezoelectric ceramics. The axis which passes through the axis of these studs is called the stud axis.
For cylindrical resonators, the stud axis defines a potential axis of symmetry of the resonator.
In some cases, "stud axis" may be called "resonator axis".