Stupid Rackmount equipment question

[SPDraver]

I have searched and searched for the answer to this question: How wide do the ears on rackmount equipment stick out from the edge of the equipment? When they say 19", do they mean from edge to edge on the ears? Or edge to edge on the euipment. I'm building a music workstation and need to know how wide to make the rackmount spaces. Thanks guys.

[r33k]

SPDraver,

 

The entire unit including ears is 19" wide. The width of the body of the unit can vary a lot, but the overall width cannot.

 

Good luck with your project,

 

Michael Erwin

Synthtank Studio

[keyoctave]

It is 19" from ear to ear as you say. The actual cover that the electronics are in usually leaves about an inch on each side so the wings (ears) can stick out. A rack mount is known as 1 space, 2 space, 3 space and so on. A 'space' is 1 3/4" high. So if you have a piece of equipment that is a '1 space rack mount' it is 19" wide by 1 3/4" high (the depth can very). A 2 space rack mount is 19" wide by 3 1/2" high, 3 space would be 5 1/4" high and so on. Some equipment has rack mount kits that you attach to it allowing the equipment to be mounted into a rack. If you are building a rack, then purchase some 'rack rails'. These are metal L shaped brackets that have threaded screw holes that mount to the inside of your rack. This will allow the rack mount equipment to line up properly along with giving proper support. (be sure to order the screws). Hope this helps.

[SPDraver]

Damn...Excellent guys! Thank you. So to clarify, I am building my desk out of 1" MDF (Was wondering if I could use 3/4" instead of 1", but not sure about strength...suggestions?) on the inner suuports of the rack, from edge to edge should 19", correct? Thanks again...this really helps. In case you were wondering...I'm modelling my desk after the much acclaimed Omnirax F2, with some slight modifications in the desktop for a rackmount Nord 3 and rack mount virus c. =)

[Byrdman]

Originally posted by SPDraver:

[QB][/QB]

I think the screws are 19" apart on center. I will check when I get home.

 

Your building an entire desk out of 1" MDF? Check your floor loadings!

[JimmieWannaB]

Byrdman - No need to check. 19 inches is the width for ear-to-ear. The holes are about 18.25 apart but that varies based on how much the rack has bowed with age Most ears have large enough holes to allow for slop.

 

Ever notice that it's near to impossible to find standard shelves that are 19" wide? I've built my set up around modular computer table pieces and the closest I could find was 18.5 and 21. Obviously, I went with the 21. The inside width was 19.75 so I just needed to add a few strips on the inside.

[synthetic]

I've built several racks. You can buy blank rack rails from Middle Atlantic and other companies. The best method is to buy two rack rails and two blank rack panels. Screw the blank panels to the top and bottom positions of the rack. You now have a perfectly true frame to build around, and don't have to worry about one side getting apart from the other. I've screwed these rails directly to 3/4" plywood and they hold a lot of weight this way.

[Byrdman]

Originally posted by JimmieWannaB:

Byrdman - No need to check. 19 inches is the width for ear-to-ear. The holes are about 18.25 apart but that varies based on how much the rack has bowed with age Most ears have large enough holes to allow for slop.

 

Ever notice that it's near to impossible to find standard shelves that are 19" wide? I've built my set up around modular computer table pieces and the closest I could find was 18.5 and 21. Obviously, I went with the 21. The inside width was 19.75 so I just needed to add a few strips on the inside.

I checked. 19" is indeed the outside edge of the ears. You want to try for about 18 3/8 between the holes on center. On one of my racks the on center distace is 18 1/2" and on the other its 18 3/16 and I have not had any trouble getting anything to fit in either. The idea of locking the geometry with a couple of blank panels is an excellent one but there is still a range of adjustment there, so you will want to measure to make sure you are not at either extreme of the adjustable range.

 

Re the shelf sizes problem - I had noticed that myself. Also why is not Hi Fi gear rack mount? I have a pile of DVD, VCR, Tuner/Amp, and sattelite decoder all balanced precariously in my living room in a pile. You would think rack mount would be a no-brainer in this marker.

[Jeff Klopmeyer]

Trivia time...

 

Anyone want to know why racks are 19" wide? Cause I'll tell ya.

 

- Jeff

[Byrdman]

Originally posted by Jeff, TASCAM Guy:

Trivia time...

 

Anyone want to know why racks are 19" wide? Cause I'll tell ya.

 

- Jeff

Actually what I really want to know is

 

i) Why is 1U 1 3/4"? It does not even seem to be a

round value in metric.

 

ii) I keep seeing bumper stickers saying "Jesus died 4U" but what rack mount gear was he using?

 

But, OK, why 19"?

[Dave Pierce]

Originally posted by Jeff, TASCAM Guy:

Trivia time...

 

Anyone want to know why racks are 19" wide? Cause I'll tell ya.

 

- Jeff

Do tell...

 

--Dave

[Jeff Klopmeyer]

The very first equipment racks were designed for operators at the telephone company (not sure if this was Bell or AT&T at the time). Like most businesses still to this day, they wanted to pack as many bodies in a single area as possible.

 

All operators were female at the time. So, 19" was measured to be the average width of their shoulders, defining the smallest work area in which they could accomplish their jobs.

 

- Jeff

[Dave Pierce]

Originally posted by Jeff, TASCAM Guy:

The very first equipment racks were designed for operators at the telephone company (not sure if this was Bell or AT&T at the time). Like most businesses still to this day, they wanted to pack as many bodies in a single area as possible.

 

All operators were female at the time. So, 19" was measured to be the average width of their shoulders, defining the smallest work area in which they could accomplish their jobs.

 

- Jeff

Fascinating.

 

I do a lot of data center work (when I'm working that is), and most of our gear is 19" rack-mount. Some is designed for open racks, often referred to as "air racks" or "telco racks". Other stuff, especially big servers, are designed for enclosed cabinets with rails front and back. But it's all mostly 19", although you'll occasionally see 23". Any idea where the 23" stuff came from?

 

Must be annoying to our colleagues in Europe and Asia that most gear is still based on our silly measurement system, instead of metric.

 

--Dave

[Jeff Klopmeyer]

Originally posted by Dave Pierce:

But it's all mostly 19", although you'll occasionally see 23". Any idea where the 23" stuff came from?

Not exactly, but I do know that there have been some pretty severe limitations on gear based on that 19" standard. The main example is not stuff that could be stacked vertically (i.e., PCB boards and so on) but the horizontal stuff, like the amount of I/O that can fit into a box.

 

I believe the 23" rack (not ever used in audio products) was specifically designed to accommodate data systems that couldn't function within the 19" standard, probably due to proximity of internal power supplies and so on (rule of thumb: heat is bad).

 

Must be annoying to our colleagues in Europe and Asia that most gear is still based on our silly measurement system, instead of metric.

Well, everything else is annoying to them. At least we're consistently annoying, as a country, rather than just haphazardly annoying.

 

- Jeff

[synthetic]

Originally posted by Jeff, Self-Proclaimed Know-It-All:

All operators were female at the time. So, 19" was measured to be the average width of their shoulders, defining the smallest work area in which they could accomplish their jobs.

I've heard a similar story about railroads. There was a story, although it might be email legend, about how the Space Shuttle booster rocket is X feet across. This was beacuse it had to fit on a rail car, which was that width because it was based on European rail cars, which were that width based on European roads which started in the Roman Empire, which were that width because it was the width of two horses side-by-side. So the width of two horses asses determined the width of the booster rockets on the Space Shuttle.

 

If you follow this logic, I'll bet you find that the new Tascam SX-1 is roughly the width of the trunk of Jeff's Nissan.

[JimmieWannaB]

Re the shelf sizes problem - I had noticed that myself. Also why is not Hi Fi gear rack mount? I have a pile of DVD, VCR, Tuner/Amp, and sattelite decoder all balanced precariously in my living room in a pile. You would think rack mount would be a no-brainer in this market.

Actually, quite a bit of HiFi gear is rack width. Most of my consumer gear (DVD, AV Amp, CD Carousel, VCR) is the same width as my "pro" stuff (mixer, EQ, power amp, AV router, patch bay). The only one that wouldn't be available at your local Circuit City (yech) is the VCR. It's a "prosumer" machine I pulled out of an old rack at work.

 

All operators were female at the time. So, 19" was measured to be the average width of their shoulders, defining the smallest work area in which they could accomplish their jobs.

I don't doubt the statement but damn, dem's some tiny women. Look around you and see how many 19" shoulder width women you see.

[jackpine]

Originally posted by Dave Pierce:

 

Any idea where the 23" stuff came from?

 

--Dave[/QB]

 

Big women

[JimmieWannaB]

Any idea where the 23" stuff came from?

Maybe it tracks sythetic's note about the width of two horse's asses determining the size of the Space Shuttle's booster rockets. -- Maybe the 23" came from two very skinny assed women.

[Jeff Klopmeyer]

Originally posted by JimmieWannaB:

I don't doubt the statement but damn, dem's some tiny women. Look around you and see how many 19" shoulder width women you see.

Actually, you just inspired me to check. So I just walked around TASCAM with a tape measure, and found that many of the ladies around here seem to roughly correspond to the 19" standard!

 

Of course, now I'll be called into the Human Resources office and be asked exactly why I'm going from desk to desk measuring women, but damnit, this is in the interest of science!

 

- Jeff

[JimmieWannaB]

Posted by Jeff

Actually, you just inspired me to check. So I just walked around TASCAM with a tape measure, and found that many of the ladies around here seem to roughly correspond to the 19" standard!

Maybe the women at Sony are just hefty (sigh). Jeff, Can I come work at Tascam?

[Dave Pierce]

Originally posted by JimmieWannaB:

Posted by Jeff

Actually, you just inspired me to check. So I just walked around TASCAM with a tape measure, and found that many of the ladies around here seem to roughly correspond to the 19" standard!

Maybe the women at Sony are just hefty (sigh). Jeff, Can I come work at Tascam?

Ah ha! Maybe Sony is where the 23" standard came from!

 

--Dave

[Brakka]

Originally posted by Jeff, TASCAM Guy:

...I just walked around TASCAM with a tape measure, and found that many of the ladies around here seem to roughly correspond to the 19" standard!

 

Did you happen to mention the word "rack" while you were measuring these ladies?

 

Hey, the history of rack dimensions is fascinating- thanks.

[Mats Olsson.]

Regarding 23", I would not be the least surprised if it is British Telecom's own version of the 19" standard. There are several 23" large-jack patchbays for sale that used to be used in telephone systems.

 

BTW, those large jacks have a cute nickname (that I can't remember right now) that is a nod to British Telecom.

 

/Mats