At 10:16 AM 2/11/2019, Fred Cisin via cctalk wrote:
On Mon, 11 Feb 2019, Jack Harper via cctalk wrote:
Hello Chuck -
I like the idea of those sliding rails - and they appear by the
link to be good to 200-pounds.
However, with the HP7970 Drives, I would worry about the moment
pressure exerted on the rack with the unit slid all the way out.
. . . The 19" rack that I have is actually fairly flimsy and I
worried about the thing flexing with the stop/start (15ms stop) of
the two Tape Drives.
Last thing I want is for the tape rack to start wandering about the
room with tape action like some of the early disk drives (I
remember reading that the original "large" UNIVAC Fastrand drum
units laying horizontal would turn circles by gyroscopic action as
the Earth rotated :)
A few hundred pounds slid all the way out will topple it.
If the center of gravity is NOT within the perimeter of the base, . . .
Need to bolt the rear to the floor, or something SOLID, and extend
the "footprint" of the front to include where the center of gravity
is when fully extended. And a bit more, so that setting a tool or
elbow on it doesn't topple it.
I agree 100% Fred... ...and once 300+ pounds of heavy ancient
computer iron begins to topple, life becomes more exciting :)
I bolted the 19" rack with the two HP7970 drives down to a 3/4" thick
plywood base about 36" square or so and then anchored that to the
concrete floor - before I installed the drives.
See http://frobenius.com/190203%20Tape%20Drive5.jpg for yet another
exciting photo :)
Best to the List -
Jack in the Rocky Mountains.
----------------------------------------------------------------------------------
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA
303.670.8375
303.670.3750 (fax)
http://www.secureoutcomes.net for Product Info.
