HP E8402A User And Service Manual page 231

Appendix B
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. Refer to Figure B-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 B-3. Attaching the Support Rails to the Rack.
Pan Head screws
Rack Mounting and Option Installation
0.5x10.32
233