> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Peter Rathlev > Sent: Wednesday, April 23, 2008 10:19 AM > To: Dean Smith > Cc: [email protected] > Subject: Re: [c-nsp] 7201 rack mounting > > > Not really on topic, but we just finished mounting three 6509-V-E > chassis; I know they come with some stub "shelves", but otherwise they > just hang in seven 4 mm long screws in each side. (It doesn't matter how > many rack mouting nuts you use, the panel you fasten to the rack is > fastened to the chassis with those seven screws.) > > The chassis itself weighs in at just below 50 kg. Add a supervisor and > some heavy line cards and you're approaching my weight, and I'm not > exactly lean. Fourteen tiny screws... I wouldn't rest in a hammock > mounted in that way. :-) >
Shear strength of mild steel is roughly 25 tons square inch. These small screws probably could each hold close to a ton each in shear force. When you have this in a rack, the force on the screws is virtually 100% shearing force, which is far different than the force exerted on the threads of a steel hook inserted into a tree. The problem is in the end mounting because the leverage exerted by the far end of the device is considerable - far in excess of 50 kg. Center mounting and there is no leverage exerted. Earthquake resistence really calls for center mounting in any kind of 2-post rack. This is why everyone is going to 4 post cabinets. The problem is Cisco doesen't really put good mounts on their gear for a 4 post cabinet. Ted _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
