NEC N8100- 1241F User Manual page 75

Only the inner rails remain screwed to the server when the rail assemblies have been removed.
IMPORTANT:
The removed rail assemblies are to be installed on the inner rails
later. To install each rail assembly on the correct inner rail, make a
mark on the assemblies. Similarly, when installing more than one
server, distinguish between the pairs of inner rails and rail
assemblies of the servers by making marks.
Be very careful not to get your finger caught in the levers or rails.
Installing the Core Nuts
Install three core nuts on the front of the rack for each of the right and left sides and also two core
nuts on the rear of the rack for each of the right and left sides.
Install three core nuts in 1U (the minimum unit of rack height). Three slots (angle holes) are opened
per 1U of a rack. Install the core nuts at the three slots. (For any NEC rack, round marks are put in
the unit of 1U.) For one core nut installed on the front of the rack, the lower nut is used to fix the
front of the rail assembly, and the upper nut is used to support the setscrew of the server. The core
nuts installed on the rear of the rack are used to fix the rear of the rail assemblies.
Core nuts
Inner rail
Setting Up Your Server 3-7
1U height