Vinten FE-55 User Manual page 16

Installation
2.
Fit the head mounting plate to the pan base of the FHR-35. Secure
the plate in position with the six screws and washers supplied with
the FHR-35.
4 mm
14
3.
Carefully lower the FHR-35 onto the FE-55, inserting the head
mounting plate base into the top column tube section. To correctly
seat the plate, rotate the FHR-35 so that a locating hole in the
head mounting plate aligns with the dowel pin on the column.