BUILDING AN INEXPENSIVE RACK MOUNT CASE FOR MUSIC GEAR


For home studio guys, getting rack boxes are a real problem. They don't make any sound, yet they can set you back hundreds of dollars. If you have a few basic tools, though, you can build cheap racks. Here's how I solved the problem. A rack is a box. Boxes are easy to build. Build a box. After messing around a bit I came up with this method for making sturdy boxes: 

 

Materials & Tools needed: 

 

3/8" Interior Plywood (1/2 4' x 8' sheet for one rack) 

8' 1"x 1" pine board strips

1" sheet rock or wood screws.

EITHER: Pre-drilled rack rails & matching mounting screws OR standard shelving rails

& 1/4" furring strips.
1/4" machine screws (with big heads)

1/4" screw tap & matching drill bits

Saw, drill, tape measure, screwdriver and/or screw bits for the drill. 


The first decision is how deep to make the box. You want it to be deep enough to completely contain the equipment, including cabling in back. So, measure how deep your deepest rack unit is, and add an inch or two for the front (so all the knobs and sliders are recessed) and four to five inches for the cabling in back. For width, the rack units themselves are 19 inches wide, but you want to add a 1/4" or so for some slack on the sides. If you're like me, you're not going to get it exactly right when you cut, so leave a margin of error. If you get it too narrow, nothing will fit!


Height? Well, a single-up rack unit is 1 3/4" high. If you need more than 12 rack spaces, I'd advise building two. These are not SKB space-age plastic boxes, so if you go too high you're going to get a hernia lifting the thing. 10-12 spaces is a good theoretical maximum. So decide on height, and add a couple of inches for reasons given below.


It's Hip to Be Square


Now you have to cut some plywood. 3/8" plywood is thick enough. You can go thicker, but you're going to end up with a heavy box. The sides will be as wide as the depth you've decided on, and as high as the height you've decided on. The top and bottom will be 19 inches wide, plus twice the thickness of the plywood you're using. Measure repeatedly to get this right, and use a T-Square to draw the cut lines, or your box won't be square.


To construct a stable box, use screws. Don't get screws that are too long, or screws will stick through the wood all over the place. If you're using 3/8" plywood, get screws no longer than one inch, as they just have to go through the plywood and into a 1"x 1" strip. When you screw your box together, don't be afraid to use lots of screws -- they hold it together after all, and adjacent screws act as strain relief for each other.


Get some 1"x 1" or 1"x 2" pine strips, cut them a couple of inches shorter than the depth of the box. Screw these centered into the top and bottom of each side, flush with the top (or bottom). At the front of the box, you'll want the pine strips recessed enough that the rack railing can fit in front of it.

 

Good Screwing Made Easy


The idea here is that to get a sturdy box, you've got to have something to screw into that's sturdier than the end of plywood. Using strips inside the box gives the screws something solid to bite into. For extra sturdiness, glue the pine strips to the sides before screwing them in.


Once you've got the strip on the sides of the box, you're ready to add the top and bottom of the box. Before you attach the top and bottom, get a rack module and put it between the sides. Then position the sides on the bottom of the box and adjust them so that the rack unit fits snug, but not tight, at the face. Mark where the sides hit the bottom of the box, and use the marks to guide you as you attach the sides to the bottom.


To do the top, flip it over and repeat the process. Now you've got a box. The pine strips used to secure screws shouldn't prevent a rack unit from fitting into the top or the bottom of the box, since most rack units are narrower behind the ears than 19".


A Rail Job


Now you want to attach the rack rails to the sides of the front of the box. You can either buy pre-drilled rack rails from Parts Express (800) 338-0531 or do what I did -- booger up your own.


To make your own rack rails, you start with those shelving rails you use to attach shelves to a wall, and 1/4" furring strips. At the front of the box, screw these to the sides of the box, with a furring strip between the shelving rails and the side. The furring strip brings the shelving rails out just enough that the rack screws will fit through the face of the rack modules.


In order to attach the rack units, you need some mounting holes in the edges of the shelving rail. Here's what you do: Select a box of machine screws with large heads, but fairly thin shafts. 1/4" screws are about as big as you can sink into the 1/2" thick shelf rack. Now go to the section of your hardware emporium where the drilling gadgets are, and find a hole tap that will match the size and thread of the screw, and the drill bit the hole tap needs to drill the hole. Then it's just a matter of marking the screw holes along the shelf rack, drilling them, and using the tap to thread them.


With the cost of all the wood, the screw tap & drill bit, the shelving rails, wood screws and machine screws, you should be able to build a couple of twelve-up racks for less than $50. They won't be SKB ATA approved shock mounted racks, but they won't cost $300 either.


If you want to get fancier, you can do things like put detachable doors on the front and back, and casters on the bottom. If you're really ambitious, you can glue carpeting on the outside, or tolex. But don't get too fancy, or you might as well have bought a commercial rack in the first place! 


Amazing 3-D ASCII Art of a Rack Case:


A single RU height is nominally 1.75 inches (1 3/4 inches). Here's the rest of the story:

 

The dimensions of a standard two space 19" rack are:

 

         |[-------------------- 19.062 +/-0.032 --------------------]|

     _____________________________________________________________________

     |   |                                                           |   |

     |   | |[------------------ 18.312 +/-0.062 ------------------]| |   |

     |   |___________________________________________________________|   |

0.312|   |   |                                                   |   |   |

     |   | o |                                                   | o |   |

     |   |   |                                                   |   |   |

0.625|   |   |                                                   |   |   |

     |   |   |                                                   |   |   |

     |   | o |                                                   | o |   |

     |   |   |                                                   |   |   |

0.625|   |   |                                                   |   |   |

     |   |   |                                                   |   |   |

     |   | o |                                                   | o |   |

0.500|   |   |[--------------- 17.750 +0.062, -0 ---------------]|   |   |

     |   | o |                                                   | o |   |

     |   |   |                                                   |   |   |

0.625|   |   |                                                   |   |   |

     |   |   |                                                   |   |   |

     |   | o |                                                   | o |   |

     |   |   |                                                   |   |   |

0.625|   |   |                                                   |   |   |

     |   |   |                                                   |   |   |

     |   | o |                                                   | o |   |

0.312|   |   |                                                   |   |   |

     |   |___|___________________________________________________|___|   |

     |   |                                                           |   |

     |   |                                                           |   |

     |___|___________________________________________________________|___|

               

1.All dimensions in inches. 

2.Extrapolate for additional height racks. 

3.The holes are to be tapped for 10-32 screws or drilled to accommodate the clips that provide a "stand-alone" nut. The latter are advantageous because they allow one to simply replace the clip/nut if one strips out a hole, rather than having to replace the entire rail. 

4.The holes in the middle of each space are actually optional, but should be included for "universal" mounting. Some gear, such as the Alesis 1622 mixer require them if all mounting holes are to have screws installed. 

5.Panel thicknesses, and therefore the desired setback of the rails from the front of their supporting members, are quite variable, and may range from 0.125 to 0.312. 


Some recommended changes to the design and construction from satisfied users:


Durable and safe for long term use, or as a retail item? Maybe, but to play it safe, some of the you might want to consider some of these ideas. Some of the attachments seem to be weak... like the 1/4" screws holding the rails. Or, the use of glued fir strips for reinforcement on the plywood... especially since plywood is a laminated layer material. Time and climate changes... cold, heat, moisture, and the like will possibly cause the layers under stress to separate from each other. After all there is a lot of weight, and money, suspended from that 1/4" screw surface.


It wouldn't take to much to adapt the basic design to a more professional, stronger, and ascetically pleasing box w/rack design. I would think, for instance, that the use of 1" bolt with nut would be a better retainer for the rails. Using washers to reinforce the attachment surface, inside and out.... and the head of the bolt on the outside to prevent snagging (and covering it with a "molding" trim of some type)... you would increase the strength by a great margin. I would also build the rack first, then enclose it with the case instead of building the box and putting the rack into it. That way, the rack will fit the equipment and the box wrapper can be adjusted accordingly for fit and consistency. Reduces the possibility of screwups with improper fit, etc.


The box, once cut and laid out, one might be assembled using "joint donuts" that are glued in place. Talk to any carpenter... or catch the “"New Yankee Workshop" with Norm Abram to see how these little devils work. They fit into simple notches cut into both pieces to be joined... act like a tongue and groove attachment for strength. They can then be backed up with a self-taping screw for additional strength at the joined surface (fewer would be needed, but the joint would be 4 to 5 times stronger this way than that in the design).


The plan makes a reference that they "won't be SKB ATA approved shock mounted racks".... but in the attachment process, why not use some sort of hard rubber or nylon spacers between the rack and the outer box to absorb shock? Besides, using the nut and bolt system I mentioned earlier, the rack with will much more secure and stable... less possibility for the rack and case to twist and become mis-shapen under use.


I think that I would also make it so that the front and back covers are easily removed... But not to easily so that they come off in transport. In that way, easy access for use on the front, and easy access for attaching cabling and such, through the rear, to the equipment.


The biggest drawback that I see to the idea is the weight that the "plywood" would add to the assembly. The box would weigh a hefty amount, without the rack and equipment. Definitely have to use a dolly for transport for one person, although there could be solid handles attached on the side for two to carry , or even cut out hand grips in the side of the box for easy pick-up and movement.


A decent method of finishing off the exterior of the box would also be needed. Simply painting a plywood surface, rough and unfinished as it is, would look rather tacky. I'm not saying that it would need to be made to look like hardwood furniture... but I think that it would need to be better than painted plywood. Maybe consider using some sort of wood vernier covering.


Changes made and recommended by one visiting musician friend:


Subject: Re: [Fwd: Interesting...]

From: Robert Angelo

To: Mike


Hey Mike :


Got this email and you're right on a lot of that stuff , that design was written to offer the most functional and cheaply designed box. But, as with anything you know you can get fancy with it .. On mine I did put a molding strip all around the box plus I used “"L" type brackets inside the case for reinforcements as well... Yeah, you can get real fancy with it , I"ve seen some people carpet the box , or tolex it , but that adds to the expense of it too. On mine I have Stanley handles on the sides... you can buy recessed type handles too to make it more fancy as well. On my case I sanded it down with a sander, and painted it black... which looks decent with the gold trim molding . You can also do a front and back cover for it too... which you can build using a detachable piano lid type hinge. You can also add rubber strips on the bottoms which I did on mine to prevent slippage and the like on where it sits. I used pre made rack rails on ours which were really cheap enough ..about $5 or so. But, the standard side screw on a commercially made rail is about 1/4" so while I agree with you it could have a better screw, that's the standard on them. Oh, you mentioned the "ATA thing"... nothing that is handmade will ever be approved for ATA shipping on planes unless you pay extra insurance on it. You have to cart it thru by some other shipping method. Actually other people make rack cases commercially but cant get ATA approval. Only SKB to my knowledge has it and that"s probably because they use that space age military like polymer plastic, or carbon fiber. But, for a stationary studio rack the design would be pretty durable and suitable ... it is for me!


Robert

 

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