Apple Xserve - Manual (Page 14)

14 Chapter 1 Installing the Xserve
Step 3: Mount Rails Loosely in the Rack
1 Place an assembled rail in the rack (it will support itself temporarily while you gather
the fasteners). The way you fit the rail depends on the rack.
 If you have a square-hole rack, start with the rail flanges inside the posts and expand
the rail between the front and rear posts until the small round guide on each flange
extends through the rail.
Expand the rails
so they fit inside
the rack posts. Position the spacer
on the outside of the
post, and over the
threaded guide on the rail.
Position the spacer so the small
block on the back engages the
square hole in the rack support. Use the screws that came
with the rail to secure the
spacer to the rail.