Bird Technologies 8578B150 Series - Manual (Page 21)

Installation
9
Attaching the 3-1/8" Unflanged Conductor
1. Attach the new Inner Conductor using the button head screw.
2. Attach the 3-1/8" Unflanged Connector with 4 socket head cap screws to
the unit by aligning the alignment holes over the 4 socket head cap screws
in the top of the unit.

Note:
The coupling must be fastened with all 4 of the screws.
Tighten evenly all around.