building drive cages & fan placement in a DVR

[notanotheracct]

so i'm about to start building 2 HD "cages". i've got a roll of aluminum, cutting tools, bending tools to make angles, vinyl grommets to possibly use to reduce vibration, and alot of hope 😀

one cage is going to be for a tivo DVR unit and my intent is to make a cage that holds two drives, one above the other, and have a fan either blow air to or away from them. there is already one fan toward the back of the unit blowing air out, so my problem is where to place the second fan. it can be in one of three positions:
1. against the FRONT of the unit, blowing air over the HDs toward the rear fan
2. at the SIDE of the unit, air can blow against the HDs where it'll end up hitting the ribbon cable
3. between the HDs and the back fan

the problems with positions 1 & 2 is that fans intake is against the case, which i'm not sure not much of a negative that might be (i'm no expert of fan/airflow). position 3 seems fine to me but i'd rather have air blow over the HDs if possible, and two fans blowing in opposite directs - i'm not sure how smart that is.

and regarding the cage itself, i'm not sure if i should make it out of aluminum strips on the HD sides to screw into, or if i should make it more like a solid 'U' shape, or of i should make it like a square wind tunnel.

thoughts? opinions?
and i apologize in advance for bad descriptions/artwork... don't send the art police after me 🙁

 

[GalvanizedYankee]

I'll stamer out what little I think I know.

Fans work best if they have atleast the width of the fan in clearance on the discharge side.
A 38mm fan should not have anything blocking it's output within 38mm of it. Same is true
of 25mm fans=25mm clearance.

If Zepper reads this thread, he can tell you where to buy HDD cages to mod. I found that
even with the use of a drill press it is very difficult to get the mounting holes for the HDDs
just right. For postage a member sent me some dead HDDs to use for mock-up work.
Using new HDDs and grinding, filing and cutting around them is unsetteling. One little drop
and the drive can be killed, let alone the metal dust.

When working aluminum pop-rivets are a must for me. I use the all aluminum jobs, even
the mandel is aluminum. Before using a single rivet to attach a mount, both surfaces that
meet are sanded and cleaned oil free. The rivet is set but the joint can still be moved a bit.
This helps with alignment. Once all is where I want it, a large drop of liquid super-glue is
touched to the seam of the joint. It will wick in very fast. In about 5 minuets the joint that
is held together by one tiny pop-rivet will be very secure for the long term.

If you need/want a pop-rivet gun I can highly reccomend the Arrow RHT300. It Froogles
at $20, has a swivel head for tight working conditions=very good kit.

That's all I got. Good luck on your project.

...Galvanized

 

[notanotheracct]

mmm... well, perhaps my HD fan for the dvr won't be as effective as i had hoped, but that's knowledge i can definitely use for the 3 HD cage i make for my actual PC.

for the mounting holes, i know it'll be a pain but i've got plenty of drills, measuring tools, marking tools, and patience to make it work. i also planned on using rivets all along, the only problem i had was finding non-white/painted ones. otherwise my rivet gun is ready and waiting. thanks for all the info, you've been my main help from this board. it's gotta be a coincidence that the old guy with the beard always proves helpful to me 😛

 

[GalvanizedYankee]

Suck up 😉 I don't even care for Harleys. Eye-Tie bikes catch my eyeballs.

http://www.mcmaster.com/ #9311K138 is what I've been using for HDD mounting.

The holes are first drilled undersize, then a small rat tail file is used to get exact placement.
I don't even try to drill them spot-on anymore. Dykem, scribe, prick punch, center punch,
drill press and they can still be a touch off.
If the 1/4" hole for the above grommets is just undersized a tad, the 6-32 mounting screw
will fit just right.

The super-glue trick works very well. The aluminum angle stock I buy from ACE Hardware
is anodized, not quite to being industrial but more than decorative. An anodized surface
will take super-glue incredably well. I make HDD mounts out of this stock.


...Galvanized

 

[GalvanizedYankee]

It just dawned on me.

You could make duct work out of thin acrylic. Tutorials are posted at SPCR and overclocker.com.


...Galvanized

 

[Zepper]

I was wondering why you plan on two drives. A stack of two properly-spaced desktop HDs (should be at least 1/4" between the drives, I like 1/2") often won't fit inside a Tivo case unless you leave the top off. Most folks just use one larger drive if they want more capacity. Anyhoo, you can get a drive bracket from http://www.evercase.com . They are in the Options list (toward the bottom of each case description) for any of their ATX tower cases. You can also get the vibe dampers for the brackets at the same time - you have to phone Evercase to buy the optional parts as they don't have e-Commerce on their web site (stupid, I know). As G-Y suggested, getting the hole spacing just right isn't the easiest thing. Most commercial brackets in cases have slightly oversized holes or slots (or perhaps one position would be holes and one slots) so they don't HAVE to get the placement exact.
. If you really want to get another drive in there and be able to close the case, consider a notebook drive. You can mount those anywhere with just a couple of strips of industrial, double-sided mounting (foam) tape (Radio Schlock carries it if you don't have a supplier for that kind of stuff already). You can get the connector adapter from http://www.geeks.com and others.

.bh.