Typical Rack Sizes? and how to build rack space into a desk.

M

Mongoo

New member
I'm building a desk for recording and will have some rack spaces on either side of it. What do I need to build these spaces into the desk? What are the typical rack unit sizes? Know any good websites concerning this?

Thanks.
 
Rack sizes, called spaces, are standardized at 19"W and 1.75"H. So a 1U (unit) rack is 19 X 1.75, a 2U is 19 X 3.5, etc.
 
The outer walls of a rack unit are always a bit more than 19" because the rack ears of audio gear are never perfect. You don't want metal ears sticking out the side of your desk. Personally I tend to give at least a 1/4" extra (total of both sides) to the walls of a rack when I'm building from scratch.

The inside has to be at least 18". Most audio gear is only 17" wide, with a 1" ear on either side. But many items are up to 18" wide, with only a 1/2" ear on each side.

For example, if you're using 3/4" wood, I would recommend putting 18-1/8" between the outer walls. Then your rack ears will stop 1/4" from each outer edge of the rack. As long as you're not using plywood for the racks, this will look nice.

The official height of 1 RU is 1.75" but again this is never perfect. For a 1U rack I would give at least 1/8" extra space; for a 6U rack I would give at least 1/4" extra space; and so on, adding a little bit for every few units.

If you have hot gear (A-D / D-A converters, tubes, etc) then make sure you have lots of air between units, too.

Oh, I make my racks out of wood -- so warping is an issue too, not just imprecise rack unit measurements. It probably won't affect you if you're building a small producer's rack. But for a wide or tall (4' +) rack you'll definitely see warping.

Post some photos when you're done! :)

Cheers,

Johann

EDIT: One thing I forgot. I never use rack rails. So my measurements above are for wooden housings, not traditional racks. I don't like rack rails, I don't like rack rash, and I don't like the added complexity in sorting out ground loops when metal chassis' are all attached via metal racks. I figure eliminating metal racks will eliminate some of the complexity in my not-quite-perfectly-wired studio.

Instead of rack rails, I place 2-4 wooden spacers between each unit in my racks. This ensures breathing room for hot equipment, too.
 
Rack rash is marks left on your rack gear when it's racked with other rack gear. (i.e. sliding one piece of rack gear in and out could leave marks on the other piece of rack gear below it. etc)

It could also be marks left by the screws or when the back of the rack ears touches the metal rack rail could leave marks too if screwed in too hard.
 
I do use the metal angle and I allow a width between the sides of 19 1/4". It's really easy if you use pre-finished MDF shelving (at least 16" wide). I work out my measurements and get it cut at Rona/Home Depot/whatever when I buy it. It makes it easier to transport and the worst bit is done. You can either use those little metal angle brackets or 2x2 when you screw it together. Remember to attach the metal angle to the sides before assembling. I set that back about 3/4" from the front edge.

Some music shops stock the metal angle. I bought mine mail-order years ago and re-use it.

I used to have a pair of racks either side below the desk down by my knees but I got fed up with that so now I have a pair of shorter racks (6U each) on the back of the desk for the items I use the most. The stuff I use only occasionally doesn't even get racked.
 
MOFO Pro: I don't have any *good* pics at the moment, but what I do have is here:

Tall rack (the one in the background)

Wide rack

The tall rack was actually built by my father years ago, to be used with 19" computer equipment. :)

The wide rack was my first woodworking project, and I didn't leave enough space on the outside rack slots -- metal ears stick out past the edge. :(

I'll try to get a close-up shot of the tall rack (which is my main one) this weekend. Also I've got a custom 6U rack, made by a guy named Beezoboy from another board, which is just lovely, and has rack rails. It might be the kind of thing Mongoo is looking to build. I'll post back when I've got a couple of shots up on the web. Hope this helps!

Cheers,

Johann
 
Mongoo,

There are some pics and diagrams of desk/rack combinations over here;

http://www.longsoughtfor.org/postn/...ame=gallery&file=index&include=view_album.php

I did one the forst half of this year but it took me six months of weekends and the occasional holiday while working around soccer nad baseball schedules for my son.

I did a modified combination of two examples modified to meet my needs.

The top looks similiar to this one - http://www.longsoughtfor.org/postn/...ame=gallery&file=index&include=view_album.php

Mounted on a desk design with a hidden recessed center slide out tray for a keybord like the bottom of this one - http://www.longsoughtfor.org/postn/...ame=gallery&file=index&include=view_album.php

There is also a Studio Buildong and display section at the bottom of this forum - http://www.homerecording.com/bbs/forumdisplay.php?f=20

I would post pictures of mine but my digital camera is in for repairs :(
:(
 
Good advice in this thread. After having made a number of racks for my studio I also recommend making the width 19 1/4" and add at least 1/4" to the total height of the rack above and beyond the 1.75" per rack space (talking about inside dimensions). If you don't create that extra space, it will be too tight and you'll have trouble getting the gear in. Also, don't forget to recess the rack rails a bit from the front of the rack. Something like 1/2" works well. Also, I've found that a depth of 18" works well for most gear, and it is easy to find wood at that dimension.
 
hey mongoo

one other way to solve rack rash (which i would agree is a pain - and how many ads on ebay do you see with "only light screw damage") is to use plastic rack bolts. i get mine from studiospares in the UK and they also have the added advantage that they come with plastic washers, meaning that you can use rack strip but still avoid grounding problems.

i've put everything in my racks with the plastic screws and never had one strip thread yet. well worth a look at.

i know i've also been gently flamed for this before, and i know the rest of their furniture is not well favoured here, but....

ikea (holds hands over head waiting for flak!) do a fantastic bedside cabinet for less than £10 (uk) and it is just about perfect if you slam in a rack strip down either side. with a little shelf mod you can fit upto about 8U in there.

have a look at the piccies at: http://www.tollboothmusic.com/stddets.htm

all those racks are the ikea units fitted with standard rackstrip and plastic bolts. the caged nuts are standard metal. i put very thin hi density foam between the units firstly to stop rack rash and secondly to further isolate and support the units.

as jtienhaara said, you have to watch some units as some manufacturers do push the limits of rack ears and don't give you very much room. focusrite are particular beggars for this and the actual 'workings' bit of the unit comes right up to the ears.

hope this helps - have fun building!
 
Regarding rack rash, I use special plastic washers with "shoulders" on BOTH sides of the rack holes. This way you can use standard metal screws and still isolate the metal of the rack unit from the metal of the rack rail. All my gear is mounted so it is isolated from the rack rails. I think Raxxess makes the shoulder washers, and I'm sure others do as well.

I don't understand why anyone would tighten down a metal screw against the metal faceplate of a rack unit. It is practically guaranteed to leave a mark and basically ruin the look of the gear. That affects resale value. For me personally, I don't even consider purchasing used gear that has rack rash around the holes. I consider it a sign of the owner not really caring about the gear, not taking good care of it, etc.
 
Great thread,

I'm planning on building some rack furniture myself, so this thread really comes in handy!

I'll post you pics of mine when I'm finished;)
 
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