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19" rack mount slide rails for old DEC equipment. What do you people use?

1944GPW

1944GPW

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Brisbane, Australia
What do you guys do for racking up your old Unibus DEC gear? I'm at a stage where I'm about to start racking up my 11/05 and peripherals in my 4' high 19" rack cabinet and am looking around at telescopic slides. I've been told that DEC used different rails for PDP-11's, PDP-8s and so forth, and these are unobtainium where I am.

Since I've mostly improvised my rack by converting a 24" high (12 RU I think) 19" TV station equipment cabinet into a 48" cabinet with a lot of cutting and welding, my first option is to build some sort of slide from scratch from mild steel bar stock and roller or kitchen cabinet bearings. This would take quite some time however, given the free time I can devote to it.

Option 2 is that there are nice generic slides available in the US but shipping alone for a set of 6 pairs is quite a few hundred US dollars, so that rules that out for the most part - eBay has a new default International Shipping rate that is often grossly inflated.

Option 3 - I can get locally available slides for such things as IBM X-series and HP servers, but these are still pricey and are a hodgepodge of styles which would need modification anyway, and I don't know if they would carry the weight of the 10-1/2" high 11/05, the heaviest of my gear.

So I'm scratching my head about ideas for slides. Do you all have the original slides, has anyone adapted a common slide in lieu, or made their own?

Thanks for any help,

Steve.
 
Thanks Al, a lot of slides there to choose from - DEC would have had a part number for them to fit the H960 rack? I looked through the 11/05 manuals but didn't see any particular designation for these.
I found some slides by that manufacter on eBay that seem like they might be a good candidate (aside from the shipping problem) http://www.ebay.com/itm/General-Dev...ails-C-300-S-126-CC3001-00-0260-/170975760771 that might be attachable to the 11/05 rotating pivot, but drilling screw holes in those seems unavoidable.

Steve
 
Most of the slides for the "modern" IBM kit are not very good and fit special clips on the server. You can usually tell this sort of rail as it has "prongs" sticking out of the top. These

http://www.ebay.com.au/itm/251058056970

look OK but I don't think they are IBM X-Series rails as these have green ends and the IBM rails are purple. I think these are SUN rails. I would say rails for the larger SUN boxes would be OK. Say for a V480 or similar but again check for mounting holes.
 
1944GPW said:
What do you guys do for racking up your old Unibus DEC gear? I'm at a stage where I'm about to start racking up my 11/05 and peripherals in my 4' high 19" rack cabinet and am looking around at telescopic slides. I've been told that DEC used different rails for PDP-11's, PDP-8s and so forth, and these are unobtainium where I am.
Click to expand...

I can only speak from my personal experience, but I do believe that you need to pay very careful attention to the actual width of the chassis that you intend to rack. They vary! It's not just a matter of "era" and "cosmetics". It's also a matter of chassis design, and widths are not especially standardized (at least within DEC gear). Furthermore, widths vary *where*you*will*put*the*slides*. Take a look at an RK05, for example, and see why it has specialized slides and how DEC managed to occupy all available space ...

A 19" rack has no more than 17.75" rail-to-rail space. DEC chassis are often, but certainly not always, a full 17" in width. That means that you have only a (nominal) 0.375" space for each of your slides. Typical modern ball-bearing rails seem to be standardized on 0.75" thickness ... so if your chassis is 16.25" wide, then life is good. If less then you have to make-up the shortfall with a shim. If greater then you won't be able to use "standard" 0.75" thick ball-bearing slides.

I suggest that you start by inventorying each item that you intend to rack, determining where the mounting points will be located, and then measuring the necessary slide-to-slide width at those points.

You don't mention your rack-depth, but typical AV/RF gear seems to be in 24"-deep racks (here in the US, anyway) but most DEC "big-box" gear is sized for a minimum of 26" depth and often more. A deeper rack gives you more space to handle power and signal cables. 24" depth will leave some chassis protruding, not to mention cables.

Your rails will need to be set up to attach at that depth, or you'll need to make modifications to "fit them" -- either by lengthening robustly (typical) or installing a second pair of "rear" rails at the appropriate depth in order to support them properly.

You should also check into the rail loading. A typical "modern" rail-set is often only intended for ~90# maximum load; I believe that your 11/05 exceeds that. So rather than the nominally 1.5" tall rails you may want/need 3" tall rails, at least for that chassis. Hard disk drives are also darn'd heavy (if not more so ... see the back-breaker RK05). So check those weights and be conservative ...

It's an arcane art I guess. Can't say that I've mastered it yet. But despite the standardization on 1.75"-per-U and 19" between-the-rails, racking-n-stacking against those boundary conditions is ... interesting. Caveat Emptor!

Good luck. It'll be worth it when you're all done :->.

(And now you can see why simply installing a pair of stout rt-angle irons with some 1/8" thick plastic sheet attached to their upper-side to reduce sliding resistance may be a not unreasonable approach ... if you're careful when you pull the chassis forward. Don't forget forward tipping of the rack under those conditions, too! Heavy stuff at the bottom, and try to only pull one chassis forward at a time ...)
 
I'm in the process of racking up my PDP-11/44 project, which will include the computer, two RL02 drives, and a Kennedy 9610 tape drive. So if y'all don't mind, I'll share what I can here, too.

My 11/44 came with its slides (woohoo!), but they're missing the rear (adjustable) rack brackets. The front (fixed, riveted) brackets are present. I haven't found a source for the correct rack brackets yet. Unfortunately, I think that the slides are not vertically centered in a rack unit, so that may complicate things.

I managed to order one pair of rack slides for one of the RL02 drives from Pinnacle Micro, minus their rack brackets. I thought I'd be getting two pairs of slides instead of two slides, based on the part number and description. I'm trying to figure out whether then need to send me another pair of slides or I need to order another pair, and I've been running around with customer service for two weeks so far. I won't be losing money or anything like a business would if their project was stalled, but it's still frustrating because I want to make progress on my project. I'm also trying to find out whether they can supply the various other bits I need including the RL02 slide rack brackets and the 11/44 rear rack brackets.

I picked up an HP 42U rack that was within 50 miles of home for $100 off eBay, and it'll be housing the project. I just got finished moving the vertical rails to set the front panels back an extra inch so that deep stuff like the tape drive will clear the door, and so the rails are spaced at about 24" front to back. I can move them again later if my first estimate of everything is wrong.

I bought a pair of 26" long full-extension slides with a rack mounting bracket kit from McMaster-Carr. They're 2" slides, made by Accuride. I hope to be able to use them with the Kennedy tape drive if its chassis is the right width. The part numbers are 63835A48 for the slides and 63835A64 for the brackets.

The rack mounting bracket kit supplied for those slides would fit the rear ends of the 11/44 slides nicely if they were lined up with a rack unit. If I can't find the proper rear brackets for the 11/44 slides, then I may get another set of those Accuride brackets, drill out the rivets on the 11/44 slides' front brackets, and then use the Accuride brackets. I think that would result in the 11/44 being out of alignment with the rack units, so it would take up 7U instead of 6U and I might need to fashion trim pieces to fill in the gaps.

If I can't find the correct brackets for the RL02 slides, then I'm not sure how I'll kludge those yet. The 2" Accuride brackets don't properly fit the roughly 1.5" slide channels on the RL02 slides.

My 11/44 pile includes four chassis boxes with almost 2 computers worth of cards. One came with the slides, and two more lack the slides but do at least have the pivots. The last one is lacking the pivots. Once I complete my project, I'll probably trade/sell/give away leftovers that I don't think I'll need for spares.

BTW, I also ordered some foam filter media from McMaster to replace the rotten front panel air filter in the 11/44. The part number is 9803K314, though I don't know yet of it's the best option.

I'll try to remember to report successes and failures here in case it can help anybody out.
 
Thank you both for your comments, I appreciate it a lot. The gear I have is a bit of a piecemeal collection, acquired mostly from eBay when the finances permit. I've been lucky enough to get a few bits with lower shipping costs in a friends' container.
Currently I have a full-height 11/05, two Diablo 31s (one non-functional), TU60 DECassette. I'm waiting on an RX02 and a slim 11/05 stateside (if the sellers ever get to sending them but that's another story).

@g4ugm - that's the type of slide I was looking at, and finding it on my local eBay too :) They only have one set which I would then need to modify again. I've looked at some of these type of rails and there is perhaps enough space between the inside edges of the inner track to drill and place an allen bolt through. Not enough room for a hex-head bolt and a slotted or phillips head might not allow enough purchase to tighten securely.

@pbirkel - you raise excellent points, some of which I had thought of as well. Indeed the gear is of different widths, I have not measured them yet but it looks like the Diablo is about the thinnest as its base is undercut somewhat. It's also relatively light, I believe it's a LOT(?) lighter than an RK05. The 11/05 chassis is 26" deep so the arse end will stick out the back of the rack a couple inches, but I'm ok with that as I intend to put a simple bumper on the bottom of the rack.
The more I think about it, the more I'm inclined to your final comment - good old angle iron. I have plenty and I can weld it up no problem, or grind or machine anything needed. These would be adjustable by virtue of a vernier-style offset hole arrangement, ie. the spacing of the rail bracket holes would be 2/3 of the spacing of the frame holes, so a few extra racking heights can be achieved. I'll draw it up in CAD to solidfy my thoughts on this.
I also have offcuts of 3mm nylon sheet stock I picked up at the same recycling place I found the original cabinet, so that can go on the sliding surfaces. My idea to support the device being worked on is a simple angle iron frame that attaches to the outer face of the rack and can be moved anywhere up or down. With an open arrangement it should allow access underneath.
Many years ago I had a General Automation SPC-16 minicomputer which had a nice feature - a 17" wide Laminex table that slid out from under the blinkenlights console. It was just right for a manual and to rest elbows on while flipping switches so I may do something similar for this.

@NF6X - just saw your comment, I super-envy your access to McMaster-Carr (they won't sell to individuals outside of the US sadly). If you have to use a rail to frame spacer, could you also try an offset arrangement of mounting holes to adjust out the 1RU gap? I would like to see some photos of how you solved your racking with modern parts. Surely not everyone has the original slides... or maybe they do.

I've been told of engineers being crushed by extending gear and overbalancing 6' racks. To that end, I've built exendable legs that slide out from underneath the sides of the bottom of the rack. They extend about 18" or so with adjustable feet. I'm hoping this will take care of that sitation as I do not relish ~50kg of 11/05 crashing on to me or the floor. I'll get to posting some photos of my rack and rail experiments soon, if anyone's interested.

Steve.
 
I would love to see pictures of your slide-out rack supports. I was hoping to find a rack with those, but I didn't. I think there was a permanent/non-slide-out stabilizer kit made for my HP 10642 rack, and it's new enough that I might even be able to find it on eBay.

I'll be happy to take detailed pictures once things start lining up. I figure that most collectors will need to come up with their own custom solution based on which original bits and pieces they manage to find, so seeing pictures of various solutions should be helpful.

Speaking of the slide-out table on your old SPC-16, I did something similar in a rack of military radio equipment I assembled a year or two ago. I got a 1U rack-mount drawer, and mounted it upside-down at desk level immediately below my primary Collins R-390A receiver. It slides out for use as a writing surface and a place to rest my arm while tuning the radio:

IMG_2863.jpg IMG_2862.jpg IMG_2436.jpg

It's sad that McMaster won't export. They are a very handy source of hardware and tools.
 
1944GPW said:
The more I think about it, the more I'm inclined to your final comment - good old angle iron. I have plenty and I can weld it up no problem, or grind or machine anything needed. These would be adjustable by virtue of a vernier-style offset hole arrangement, ie. the spacing of the rail bracket holes would be 2/3 of the spacing of the frame holes, so a few extra racking heights can be achieved. I'll draw it up in CAD to solidfy my thoughts on this.
I also have offcuts of 3mm nylon sheet stock I picked up at the same recycling place I found the original cabinet, so that can go on the sliding surfaces. My idea to support the device being worked on is a simple angle iron frame that attaches to the outer face of the rack and can be moved anywhere up or down. With an open arrangement it should allow access underneath.
...
I'll get to posting some photos of my rack and rail experiments soon, if anyone's interested.
Click to expand...

Yes, it belatedly occurred to me that you were handy with the scrap iron :->. I make do with heavy aluminum, when needed, which is easier and more convenient for me to work. I'd definitely like to see how your design(s) shape up -- post diagrams and photos please! While I understand the vernier concept, I'm not sure that you can make it work with less than 3U and then I'm wondering whether you can guarantee two-hole alignment for strength. 6U ought to give you plenty of opportunities for at least 2-hole alignment. Definitely need some engineering diagrams ...

Nylon sheet stock is great. I need to find some ...

How (specifically) are you thinking of attaching angle-frame to rack-front? Not using the rails themselves I presume?

[NF6X: Thanks for the McMaster-Carr references!]
 
Equipment racking is one of my favorite pastimes! Fortunately have several original DEC racks with front and back rails and some experience working with adapting drives and systems to non-DEC rails. First think you will find that the General Devices rack rail systems was stock on the CPU, RX an RK drive units with the huge two RU pivot systems being used on the CPU and the one RU units for the RX-01 and 02 The pivots allow you to extend the Unibus system completely out of the rack and tilt it to a ninety degree angle to allow access to the underside. Just remember that the rack has to have front runners to support the weight of the system when it’s extended. The RL drives are another matter though being they have some stupid system of aluminum slides that appear to be custom to only that drive, great when you have all the parts because they are real useful in servicing the drives pulling all the way out and remove two screws and the drive lifts right out for removal but the size of the drive and location of the mounting holes are all far from anything I have seen before. I have mounted a set of General Devices rails on a RL drive before but that requires drilling out the new holes on the slide rails and mounting the tracks for the rail on the inside of the rack rails to get clearance. If you have one of the racks that use clip on nuts that’s not a big deal but on a threaded rack rail it’s a problem. Saw that you mention that the racks you have come from a television operation and wanted to say that television broadcasters are a great place to look for racks and slide mounting components. With the adoption of digital broadcasting every broadcaster has tons of old analog junk that is worth nothing, items like analog waveform monitors, analog monitors and processing equipment are littelery being sent to the scrap yard and all that stuff was in most cases installed in General Devices rack rails. I have saved many pounds of this stuff but the displays and waveform monitors themselves are being thrown out or sent to recycling. Here is a link to a YouTube of my Unibus and Qbus system in racks; if you look closely you can see the front runners on the 11/34 rack.

http://www.youtube.com/watch?v=vV5gH__xNF4

Qbus
 
Ray,

It's possible that there would be amateur (ham) interest in those NTSC waveform monitors. Although it's kind of off topic, I have ATV gear and would gladly give a free (zero dollar) late model NTSC waveform monitor a home. Even a vintage computer hobbyist with interest in the NTSC output might want one. I think a bunch of us here plan to be at Timmonium, and so since you seem to come across this broadcast stuff easily, if you haul any to Timmonium we can provide beer money.

And, General Devices chassis-traks also! I have wiped out my local surplus place.

Lou
 
Don’t know if I can get them back but will try, just sent four Tektronix 1480R waveform monitors to recycling. All working units and if they have not been taken off site will bring them to Timonium and you can have them. Analog NTSC day is done. At MPT we have one of the old high power analog transmitters sitting in a parking lot for a year now, all the rest are basically scrap. They have zero resale value. One of the translator sites I take care of in Delaware had a 5 kW analog transmitter and ended up getting a dumpster and disassembling the transmitter part by part and throwing it all in there. Have a friend up north who tells me of a television site on top of a mountain where they removed the analog stuff and pushed it down the side of the hill for fun, wonder if someday there will be analog television collectors who would long for what we consider junk today but then again there is not much you can do with a 30 kW IOT analog transmitter that requires three phase 480 volt and a liquid cooling system. Sometimes I miss the big analog stuff. The new smaller solid state ATSC transmitters just have a on and off button where the old klystron stuff required some amount of skill to operate. The dual 30 kW transmitter out in the parking lot required at least an hour’s attention and adjustments to get back on line if it was off for more than fifteen minutes but the solid state ATCS transmitter is just pushing the on button.
 
Hi All;
QBus, I would Love to have gotten All the Analogue TV stuff that You have thrown away, But the Shipping alone would Kill Me, not to say anything of where to put it.. Even If it would/could be free.. I have a couple of Old Analogue TV's (1946 and 1948 RCA)..
THANK YOU Marty
 
NF6X said:
BTW, I also ordered some foam filter media from McMaster to replace the rotten front panel air filter in the 11/44. The part number is 9803K314, though I don't know yet of it's the best option.

I'll try to remember to report successes and failures here in case it can help anybody out.
Click to expand...

How did the foam filter media work out?

Also, in case anyone else has my particular space-quandry, there there are some very nice General Devices slides that have been up on eBay (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=191082814853) for a while now. While you have to buy five, IMO they are well worth it (particularly as shipping is included and these things are *heavy*)! I've acquired a set and despite the posted identification information (and box labeling), these are absolutely identical to the CTHS-118 slides. With the rear-bracket they will fit up to a 26" depth, although I do wonder a bit about their load-bearing strength in that configuration.

Although the actual slide-length is only 18", at full extension you get 23.63" assuming that you use the suggested 2" offset from the chassis-front when you attach them. With a BA11-A that's sufficient to expose almost the entirety of the power supply, and certainly ample to expose modules and use module-extenders (which would require only about 18-19").

Although it would be nice(r) if they were longer, and really nice(r) if they pivoted, they're a heck of a lot better than anything I'm likely to ever find, short of the original "factory installed" slides specific to the chassis -- which I find myself (alas) short of ... a not uncommon complaint :-<.

Two thumbs up, way up :->.

YMMV (Your Mileage May Vary), of course ...
 
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