The neck and Convolution I.D. are equal to the nominal I.D
The neck O.D. is equal to the convolution O.D.
The neck I.D. or O.D. can be specified within the range of the I.D. to the convolution O.D.
The trim line is at the tangent point of the convolution O.D.
The trim line is at the tangent point of the convolution I.D.
Series 7500 bellows with Standard, Style A, or Style B neck trims can be specified with inside or outside bands which increase the thickness for welding or added reinforcement. The band thickness is approximately 2.5 times the bellows thickness. The bands are attached by resistance seam welding for sizes 1" through 48" and by edge welding (GTAW) for larger sizes.
Caution: The use of bands is not recommended for vacuum applications requiring a mass spectrometer helium leak test. See Vacuum Applications for recommended welding methods.