Mounting HP7970e 9-Trk 1/2" Tape Drive

[Brent Hilpert]

On 2019-Feb-06, at 4:19 PM, Chuck Guzis via cctalk wrote:
> On 2/6/19 2:29 PM, Brent Hilpert via cctalk wrote:
> 
>> (I take it you mean "now look at the -left- side".)
> 
> Well, you know, my *other* right... :)
> 
>> However, looking at my 7970A, it appears you could separate the cast-Al transport frame from the chassis box
>> by unscrewing the 4 exterior left-side hinge screws, as well as detaching all the cabling between them involving
>> a wire harness and a dozen-or-so plugs.
> 
> Swing the drive assembly out from the back cover--you'll note that the
> pivot points on the two hinges are about 1" away from the cover flange.
> You've got plenty of room to drill your mounting holes from the *rear*
> of that flange.  You might even have enough clearance for a
> countersink--but that may not be necessary--the frame casting only
> extends in from the left about a half-inch--you may even clear some
> oval-headed screws or get away with some truss-head screws.
> Alternatively, could mill a slight relief in the casting to clear the heads.
> 
> I think it's doable without removing the drive from the cover.

Granted you could drill the holes from the rear of the flange, however from what I can see the hinge design doesn't look
like it will allow the transport frame to swing far enough to clear access for the screwdriver shaft to tighten the screws from the front
(might swing to around 110deg, but not to 170-180).
The 2-1/2" thick transport frame pivots near the middle of it's thickness, at 90deg half the thickness is still well across the flange.
You'd need a ~ < 1" clearance right angle screwdriver to fit between the flange and the transport frame,
or bolt head screws and box wrench which then necessitates the milling of clearance for the heads out of the cast frame.

I might consider the transport removal approach next time I have to mount mine - 
even though I have the proper mounting bracket - just to split the weight up.
I did once do a one-person free-lift mount of the thing, but that was about 20 years ago.


>> For loading concerns raised by Jay, in both cases (designed-for steel
>> bracket vs drilled flange) the weight of the drive ends up being 
>> borne by 4 rack-screws on the left and 3 on the right. The difference
>> would be steel vs Al bearing down on the 4 screws on the left, and
>> some altered bending moments on the left side of the Al chassis box
>> around the flange, offhand I wouldn't think it would matter.
> 
> I tend to agree--the force is mostly downward on the front of the drive.
> I suppose that you could reinforce the aluminum housing with some steel
> bar backing up the mounting flanges, but that seems like overkill to me.