[c-nsp] 7201 rack mounting

[Peter Rathlev]

Well, seems I was overlooking some simple facts about the mounting.
Thanks for the points on and off list. And yes, of cource Cisco has done
the calculations. To my untrained eyes it just appeared unimpressive. I
stand corrected. On top of that it was OT. :-)

The drooping of 1U boxen is the real problem. No matter how much we
tighten screws we have the same problems with e.g. ASA5550s and to some
extent 3750s. And the 7201 isn't exactly a baby compared to those.

Regards,
Peter
 
On Wed, 2008-04-23 at 14:42 -0400, Fred Reimer wrote:
> You have several things to consider before you start worrying about the 14
> screws.  First is the shear force necessary to break the screws, and second
> is the fact that a properly mounted chassis will result in the friction
> between the mounting gear and the rack post taking up most of the weight and
> considerably less weight being put on the screws.  It is even possible for
> the screws to be under little or effectively no direct shear force.
> 
> I'm not a mechanical engineer, but I'm sure that Cisco did the proper
> engineering to ensure sufficient screws if mounted properly.  The only
> related case I'm aware of is a manufacturing defect where the side handles
> on 6500 chassis would break off; I'm glad I'm not the one that called TAC
> the day that was discovered!
> 
> 
> Fred Reimer, CISSP, CCNP, CQS-VPN, CQS-ISS
> Senior Network Engineer
> Coleman Technologies, Inc.
> 954-298-1697
> 
> 
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Peter Rathlev
> > Sent: Wednesday, April 23, 2008 1:19 PM
> > To: Dean Smith
> > Cc: cisco-nsp at puck.nether.net
> > 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. :-)
> > 
> > Regards,
> > Peter
> > 
> > On Wed, 2008-04-23 at 11:17 +0100, Dean Smith wrote:
> > > Anyone else shocked at the appalling rack mounting supplied for 7201
> > ?
> > >
> > > Single "ears" at either front or back is simply not good enough for
> > >  that sort of box. Look at any 1U server (equivalent value/weight)
> > and
> > >  you'll get a decent adjustable rail that can go front to back and
> > >  offer a proper stable mounting
> > >
> > > Our first 7201 install is drooping alarmingly (and I dont think its
> > >  cheap rack rails)
> > >
> > > At cisco prices i dont expect to have to go and buy additional
> > >  shelves/brackets just to get an acceptable rack mount solution !
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