Kinematic Base 6KB is used for repeated positioning of groups of units mounted on its platform. A platform has M6 mounting holes. Alternatively, fit an M6 screw through a clearance hole from beneath. You unhook the platform from the bottom plate of the kinematic base and stow it away with all the units still mounted. Later you replace the platform, just as it was, with a repeatability of several arcsec. The bases use a kinematic scheme, where three steel balls register with a cone, a v-groove, and a flat. The balls and register are of hardened polished steel. Hooks of spring steel prevent a platform move by accident.

A bottom plate
of kinematic base is
fastened through clearance
holes or a slot. 6KB131
has a revolving mounting
disk - a degree of freedom
of positioning.