[time-nuts] Excellent equipment rack

Tue Jun 11 17:27:21 UTC 2019

Hi All;
I have found when rack hunting it is best to look at local test equipment auctions. Even really nice racks often do not receive any bids and more importantly no shipping. In my labs I use exclusively Agilent/Keysight because they are exceptional quality and parts a commonly available. The one minor problem is they are a touch narrow, and some items like Wavelek calibrators are a really tight fit, but workable. I find in local auctions when they show up they are (like other racks) usually very inexpensive. The trick is if you have any plan to go to racks in the future start looking early and buy when you see them even if not yet prepared to use them and store them until needed.
Hope that helps

Tom Knox

303-554-0307

actast at hotmail.com

"Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bob Albert via time-nuts <time-nuts at lists.febo.com>
Sent: Tuesday, June 11, 2019 9:59 AM
To: Perry Sandeen via time-nuts
Cc: Bob Albert
Subject: Re: [time-nuts] Excellent equipment rack

Very interesting!  Recently I had a somewhat similar experience.  My neighbor was throwing out some shelving that looked like what I need.  It was gray steel, all the vertical parts needed but no shelves.  I made shelves from plywood and ended up with a nice addition to my lab.  To make it mobile I sat it on a dolly that fit almost perfectly so now I can move it.
I put my VNA and some tools on it and it's a perfect fit in the corner of the room.
Just because I am an electronics engineer doesn't mean I can't do mechanical stuff.
Bob
    On Tuesday, June 11, 2019, 08:00:43 AM PDT, Glenn Little WB4UIV <glennmaillist at bellsouth.net> wrote:

 Here is what a U is:

Main article: Rack unit <https://en.wikipedia.org/wiki/Rack_unit>

Racks are divided into regions, 44.50 millimeters (1.752??in) in height,
within which there are three complete hole pairs in a vertically
symmetric pattern, the holes being centered 6.35 millimeters (0.25??in),
22.25 millimeters (0.88??in), and 38.15 millimeters (1.50??in) from the
top or bottom of the region. Such a region is commonly known as a *U*,
for /unit/, or, in German, *HE*, for /H??heneinheit
<https://de.wikipedia.org/wiki/H%C3%B6heneinheit>/, and heights within
racks are measured by this unit. Rack-mountable equipment is usually
designed to occupy some integer number of U. For example, an
oscilloscope <https://en.wikipedia.org/wiki/Oscilloscope> might be 4U
high, and rack-mountable computers are mostly between 1U and 4U high. A
blade server <https://en.wikipedia.org/wiki/Blade_server> enclosure
might require 10U.

Occasionally, one may see fractional U devices such as a 1.5U server,
but these are much less common.

The height of a rack can vary from a few inches, such as in a broadcast
console, to a floor mounted rack whose interior is 45 rack units (200.2
centimeters or 78.82 inches) high, with 42U being a common
configuration. Many wall-mounted industrial equipment enclosures have
19-inch rack rails to support mounting of equipment.

A R-390 is 10.5 inches tall so it is 6U.

Your rack could be drilled for using mounting screws of: 10-32, 12-24,
M6 or require a nut plate for equipment mounting.

73
Glenn

On 6/11/2019 2:02 AM, Perry Sandeen via time-nuts wrote:
> Yo Bubba Dudes!,
> Needing to go vertical with my test equipment I went bottom feeding for an equipment cabinet on ebay.
> To make a long search story short: they were way too expensive, too heavy to ship and too far away for pickup.
> So I kept searching and finally came across what was listed as *42U Four Post Open Frame Server Data Rack 19 inches.?? Adjustable depth 23 to 32 inches.ebay number 152319524877.Sold by Raising Electronics for US $188 and free shipping.
> I was unsure what a *U* height meant put it seemed tall enough so I bought one.
> I was a little apprehensive about this being a Chinese metal product.?? I was very pleasantly proven very wrong.
> Although it only comes with a picture of an assembled unit it has been engine ed so there is no way you can assemble improperly. The four posts are all equal and can be installed with any end up or down and the top and bottom brackets will fit.?? It comes with the exact 50 M6-20 head bolts and nuts needed for assembly.?? The nearest SAE equivalent bolt size is 1/4 20 x 1/2L which I purchased to hold L shelf brackets to the frame.
> I set the depth of mine to 26 inches so my 5370's fit well and I had space for both power and BNC cables to be inside the frame.
>
> This rack is designed to be bolted to the floor.?? Wanting to be able to move it, I cut a piece of 3/4 inch plywood a little longer and wider then the base footprint and installed 4 inch tall Harbor Freight swivel casters on the four corners for ease of movement in any direction, even on floor carpeting.?? After assembly it was 6 ft 9 inches tall.
>
> Now this being a bolted together *skeleton frame* it is prone to twisting and or becoming a parallelogram sideways.?? To prevent twisting, I fitted a plywood board on the top bolted to the top front and rear angle pieces.?? To prevent a side-to-side movement required an 8 inch wide piece of scrap aluminum plate bolted to the rear vertical posts.?? This is easy to do as there are a plethora of precision spaced holes available.
> There was some very serious thought given to the vertical post design.?? It has six 90 degree folds done in such a way that the inner edge on each outer side gives a 19 inch opening.
>  ??However behind it is as inner fold where one can install recessed L shaped brackets. Now the inner fold is about and inch narrower than the outside edge.This allows making a wider shelf that can *float* on top the brackets but can't slide out either end.
> This was very useful when configuring the instrument arrangement.
> I also found that with the bottom shelf being just 6 inches above the floor I was able to install more equipment in the same vertical space than in my previous normal sized equipment cabinet.
> Another bonus with this type of configuration is that it's easier to keep the equipment cool and it's much lighter.
> Regards,
> Perrier
>
>
>
>
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--
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Glenn Little                ARRL Technical Specialist  QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM  NRA LM  SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

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