I plan on doing a built in rack outside my room. The obvious choice is to use rack rails. Although, if you plan on having a tall rack, can the rails really support the weight? I guess what im asking is how is the back supported? My Denon 3808 is a tank. I know they make shelves for components not rack mountable. Is it just as simple as adding another set of rails in the rear? Or are there special rail that can be added to the rear to offer support or "shevled" components?

The reason im asking is my rack will hold:

Denon 3808
Oppo BDP-83
QSC RMX-2450
5 QSC RMX-850
Plus the rest of the stuff for the house. Thats alot of weight without support.

are you talking about using a 2 post rack vs 4 or are you talking about the rails that act as a sliding shelf for some devices?

I have a 2 post rack mounted sideways in my closet. Not optimal but most of my bigger gear has rack ears so they are fully self supporting. I have angle iron from the 2 posts to the side wall of the rack to help keep it from wanting to tip and of course it is bolted to the floor.

If I were to do it again I would get a 4 post rack, mostly to allow for extra support for the wires that comes out the back. 4 post racks can use lacer bars to clean up the wires.

I plan on doing a built in rack outside my room. The obvious choice is to use rack rails. Although, if you plan on having a tall rack, can the rails really support the weight?

Think about it this way: unless the equipment is really deep with its mass way in the back, most of the weight ends up being straight down on the rails. There is a tipping force trying to make the rails fall backwards but it takes relatively little to counteract it. When mounting the rails you need to focus mainly on the shear force pushing straight down on the rails, and make sure you have enough bolts (and/or support under the foot of the rails) to handle that.

My Denon 3808 is a tank.

The Internet tells me it's about 40 pounds, which should not be a problem especially if you get a shelf sized to it (MA's custom shelf database says it takes 5U).

I know they make shelves for components not rack mountable. Is it just as simple as adding another set of rails in the rear?

Shelves usually mount to the front rails only. The ones that require rear rails are typically for things in the hundreds-of-pounds range, or for situations such as a computer server or flip-up screen where you need the equipment to pull out on drawer slides.

The MA custom shelves are really nice, with venting all around and faceplates cut to fit the equipment. They mount only to the front rails and are sized appropriately. The main downside is that the cost can add up quickly if you're doing a big stack of equipment:

http://www.stayonline.com/images/menu_imgs/rsh-custom-shelf.jpg

If I were to do it again I would get a 4 post rack, mostly to allow for extra support for the wires that comes out the back. 4 post racks can use lacer bars to clean up the wires.

Yeah, this. I have a 4-post server rack for some of my gear and it really does make wire management a lot easier. My in-wall rack only has front rails and I sometimes think about trying to retrofit lacing bars behind or alongside it. If you have the room for a 4-post you should really consider it for this reason alone.

When building a custom avoid this commen mistake. A component rack width is properly touted as 19inches. However the actual rack rail spacing width is 19&1/8 to allow some tolerance.

When building a custom avoid this commen mistake. A component rack width is properly touted as 19inches. However the actual rack rail spacing width is 19&1/8 to allow some tolerance.

Yeah the tolerances are very tight for this stuff and you need to get the rails just right or the holes might not line up. While it's true most rack ears have elongated holes to allow for some variation, I've found that those holes aren't always centered the same way, so if the rails are a bit wide some equipment will fit fine and others not at all. Make sure your design allows you to tweak the rail separation and don't forget to account for any framing you might want.

When I did mine, I made the rough framing quite a bit wider, lined the interior with painted MDF, used more wood with rubber edging to get it close and then shimmed the rails precisely with metal and cork+rubber washers. Lag bolts go from the rails all the way into the rough studs. I still had to adjust the spacing a few times before all of my equipment would fit.

EIA-310-D is the official specification. I dug these numbers up somewhere along the way:

- distance between the interior edges of the rail front faces = 17.75in +/- 0.03in
- distance between hole centers = 18.3in +/- 0.03in
- total front space for equipment faceplate and mounting tabs = 19.45in

Also: better to be a tiny bit wide than a tiny bit narrow, because some shelves and equipment cases are as wide as the spec allows and won't even fit between the rails if they're too close together.