HP E840 A Series User And Service Manual page 27

Chapter 2
4. Attach the support rails to the rack's inside vertical rails. The support
rails must be positioned behind the bottom channel nuts installed in
Step 3 (Figure 2-3). Use four channel nuts and the four 0.5x10-32
support rail-to-rack pan head screws to secure the rail.
Position Rail Behind
Bottom Channel
Nut
Figure 2-3. Attaching the Support Rails to the Rack.
0.5x10.32
Pan Head screws
Rack Mounting and Option Installation 27