19 Jan
2015
19 Jan
'15
5:28 a.m.
I?m in the process of building another HP2000/Access TSB system. I pulled a
7970E tape drive out of a shipping container (I had not opened the shipping
container since I bought it about 8 years ago). When I got the unit on the
bench to give it a going over, while it looked pristine ? someone had
dropped something very heavy (heavy enough to severely deform ?? steel) on
the top of the unit.
My thought (given there?s not a shortage of open space inside the chassis)
was to put a car jack inside and jack it up thus pushing out the top. My
concern there was that there would be an ?equal and opposite reaction?).
Perhaps a 2x4 that goes side to side under the jack would alleviate this.
But on freenode #classiccmp (where I hang out pretty much every night),
PJustice and Sark both had similar ideas for an alternative approach that
took advantage of the fact that the top of the chassis has a lot of vent
holes on top. I implemented their approach and it worked very well so I
thought I?d document it with pictures and post here. I should note that this
approach only works because the angle iron I used was 14ga. Anything less
would just bend itself.
If I had facilities to cut the angle iron, I would have put a piece on top
and on the bottom but I don?t. Failing that, I just had to pick specific
spots on top to ?pull out? more carefully. As you know when steel bends it
stretches so it would be impossible to get it back 100% perfect but I?m
pretty pleased with the results. If you want to use this method and don?t
have convenient holes already present from the manufacturer, you could
always drill one or two holes to make it work. Note that without the wood
blocks you can pull it straight but it might bend back (albeit less so), but
with the wood blocks you can pull it further than straight so it bounces
back ?mostly straight?.
http://www.ezwind.net/hp2000/7970E/
And if you want to follow the build of the 2000/Access IO-rack (which holds
tape, terminal controller and bulkhead, and disk controller subsystem):
http://www.ezwind.net/hp2000/IO-Rack/
THANKS SARK AND PJUSTICE J
J
24 Jan
24 Jan
11:41 a.m.
m?n 2015-01-19 klockan 07:28 -0600 skrev Jay West:
My thought (given there?s not a shortage of open space inside the chassis)
was to put a car jack inside and jack it up thus pushing out the top. My
concern there was that there would be an ?equal and opposite reaction?).
Perhaps a 2x4 that goes side to side under the jack would alleviate this.
But on freenode #classiccmp (where I hang out pretty much every night),
PJustice and Sark both had similar ideas for an alternative approach that
took advantage of the fact that the top of the chassis has a lot of vent
holes on top. I implemented their approach and it worked very well so I
thought I?d document it with pictures and post here. I should note that this
approach only works because the angle iron I used was 14ga. Anything less
would just bend itself.
For car body repair it exists a method with spot-welded pins:
the pin is specially done to be able to spot-weld it with a electric arc
welder.
pull at them using slide hammer
remove the stub and clean up the damage afterwards.
This method will unfortunately destroy the zink layer.
Look for stub weld.
12:10 p.m.
My thought (given there?s not a shortage of open space
inside the chassis)
was to put a car jack inside and jack it up thus pushing out the top. My
concern there was that there would be an ?equal and opposite reaction?).
Perhaps a 2x4 that goes side to side under the jack would alleviate this.
But on freenode #classiccmp (where I hang out pretty much every night),
PJustice and Sark both had similar ideas for an alternative approach that
took advantage of the fact that the top of the chassis has a lot of vent
holes on top. I implemented their approach and it worked very well so I
thought I?d document it with pictures and post here. I should note that this
approach only works because the angle iron I used was 14ga. Anything less
would just bend itself.
Bed-frame angle iron is much more rigid than perforated or slotted angle
iron.
Harbor Freight sells 4-ton and 10-ton "porta-power" hydraulic units.
(pump, rams, extensions, variety of endpieces, etc.)
I have a 10-ton kit if anybody in the Berkeley area needs one.
I might still have a slide-hammer or two.
4:19 p.m.
Fred wrote...
----
Bed-frame angle iron is much more rigid than perforated or slotted angle iron.
----
That wouldn't have worked well at all. The angle iron that I used worked because it
had many many holes in it allowing me to put the bolt to pull precisely where I wanted.
J
12:40 p.m.
On 01/19/2015 05:28 AM, Jay West wrote:
I?m in the process of building another HP2000/Access
TSB system. I pulled a
7970E tape drive out of a shipping container (I had not opened the shipping
container since I bought it about 8 years ago). When I got the unit on the
bench to give it a going over, while it looked pristine ? someone had
dropped something very heavy (heavy enough to severely deform ?? steel) on
the top of the unit.
Well, if this were my unit, I'd remove the warped panel (it looks like
aluminum to me). Drilling out the rivets shouldn't be a problem.
Then I'd put it on my English wheel with a flat anvil and roll it
completely flat--and then reattach with screws or rivets.
This is why you should talk to a competent auto body shop for whom, once
you remove the panel, the work should be a few minutes of child's play.
FWIW,
Chuck
P.S. English wheels are wonderful--not only can you stretch metal to
form a curve (e.g. a car fender), but you can also "shrink" it (to
"unstretch" the metal from a dent.
4:43 p.m.
Chuck wrote...
----
Well, if this were my unit, I'd remove the warped panel (it looks like
aluminum to me). Drilling out the rivets shouldn't be a problem.
Then I'd put it on my English wheel with a flat anvil and roll it completely
flat--and then reattach with screws or rivets.
This is why you should talk to a competent auto body shop for whom, once you
remove the panel, the work should be a few minutes of child's play.
----
My very first thought was to drill out the rivets. If the rivets were
originally pop rivets, I would have done this (sheared off the pop rivets,
take off the plate, flatten, and re-pop-rivet or bolt). But HP quality is a
bit better than pop rivets and I aimed to preserve that (come to think of
it, I don't' think I recall seeing pop rivets anywhere in the HP gear I
have). It's all aircraft style flush rivets that are sanded down & polished.
At times, you need a magnifier to even tell it's a rivet.
So long story short, I wasn't going to take that gorgeous smooth polished
surface and replace it with bolts or screws. But for something that was
pop-rivets, you betcha, I'd have gone that route.
J
5:22 p.m.
On 01/24/2015 04:43 PM, Jay West wrote:
So long story short, I wasn't going to take that
gorgeous smooth polished
surface and replace it with bolts or screws. But for something that was
pop-rivets, you betcha, I'd have gone that route.
I understand, I guess--but who's going to see it? ;)
You can get flush aluminum standard rivets--they're not terribly hard to
set. I've also got a few underlug flush-head screws (no slot), which,
if you can get some, should preserve the exterior appearance.
FWIW, if you're looking at drilling the buggers start with a good center
punch and a very small bit--and then drill that with a bit slightly
smaller than the rivet shank only down as far as the head depth. Then
you'll be able to insert a rot of the same size and smartly snap the
head off without affecting the original hole.
Musical instrument repair shops also have special tools for working
dents and wrinkles out of brass. They range from a "dent machine" that
looks like an English wheel, with the wheel turned 90 degrees. Small
portable dent rollers, such as a "Fast Eddie" are also used.
Good luck!
Chuck
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cclist＠sydex.com -
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