DEC Rackmount 7000 AXP Installation And Owner's Manual page 40

Installation
7. Install a bar nut on the left front rail behind the 26th, 27th, 28th, and 29th
holes up from the datum line by aligning them with the holes and installing
screws in the 26th and 28th holes up from the datum line (see Figure 2–3).
These are used for securing the LSB chassis, in the closed position, to the
rail.
8. Install a bar nut on the left front rail behind the 6th, 7th, 8th, and 9th holes
up from the datum line by aligning them with the holes and installing screws
in the 6th and 9th holes up from the datum line (see Figure 2–3). These are
used for securing the LSB chassis, in the closed position, to the rail.
2–10 Installation