CM Cosmos HDD Suspension Tutorial

Enclosures and acoustic damping to help quiet them.

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CM Cosmos HDD Suspension Tutorial

Post by silence » Tue Aug 12, 2008 6:05 am

Long time no post guys...

I've had these pics for a while but never got around to posting them. It seems the initial impressions of this case have turned the SPCR crowd away from it due to the significant amount of work the case needs to be made acceptable for quiet/silent computing. I purchased this case for the immense internal volume, which makes it 10x easier to work on than a P180. I also very much like how all HDD storage is condensed into one area rather than separated like the P180 series.

Anyway, I took some sequenced photos of the HDD suspension installation procedure I used for this case. It's rather simple using 1.8mm Stretch Magic and has held up very well for about 8 months so far.

This where you'll be working. Notice that I've already done several of them.

Measure out twenty inches of Stretch Magic. This gives you a few extra inches to make tying the knot easier.

Feed the Stretch Magic around the upper and lower retention slots. In this case you can see I'm working with the outer side of the slot second from the left, lower array.

Now, using needlenose pliers or similar, pull the two ends of the string taut and secure them with the pliers.

Using a set of Vise-Grip style locking pliers, set the very end of the plier teeth so that when the pliers are locked closed they are approximately 1mm apart or slightly less. You want to be able to grab the Stretch Magic firmly without tearing it. Clamp the pliers on the Stretch Magic directly behind where you have secured it with the needlenose pliers.

Ensure that the two lengths of Stretch Magic held by the locking pliers are roughly equal in length. If not, use the needlenose pliers to hold them, release the locking pliers, and repeat until they are equal.

Now take both ends of the Stretch Magic and tie them together using the knot shown, or a know of your choice. You may wish to double-knot them, although bear in mind you will need to cut the Stretch Magic longer to accomodate additional knots.

Once the knot(s) have been tied, use some quick-dry super/CA glue and squeeze a few drips on to the knot. You may wish to leave the locking pliers in place for about 20-30 more seconds so the glue can cure before removing them - when they are removed, tension will be placed on the knot and if it is not tight, you will be repeating this step.

Here is the end result with the drive cage full of drives. Note that each of them hangs close to the cage edges but does not touch - this ensures that the drive will not fall several inches should the suspension fail. I have used two lengths of Stretch Magic, one on each end of the drive, though you may choose to use one in the middle as well. To mount the drive, simply twist the middle section of the Stretch magic and pull the two pieces apart, which leaves a "hole" between them with the twists in the material above and below; slide the drive through this hole and adjust as necessary.

A picture of the 1.8mm Stretch Magic for reference.

Please feel free to ask questions and request more pictures. I will have the case apart to install some new fans in a few days and will be taking pictures for another tutorial on noise dampening and airflow modification then.


Dom (silence)

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Post by silence » Wed Aug 13, 2008 12:20 am

100 views and no replies?

Even if you don't have a Cosmos, some feedback would be appreciated in the way of fixes/additions/additional information etc.

Thanks all.

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Post by frenchie » Wed Aug 13, 2008 11:13 pm

Nice tutorial !!!
How "stretchy" is that strech magic ? Would it hold, for example, a drive in an enclosure (I'm thinking Scythe Quiet Drive, 860g + weight of HD) ?

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Post by jhhoffma » Thu Aug 14, 2008 6:09 am

frenchie wrote:Hi,
Nice tutorial !!!
How "stretchy" is that strech magic ? Would it hold, for example, a drive in an enclosure (I'm thinking Scythe Quiet Drive, 860g + weight of HD) ?
It's stretchy enough, but with more weight you're going to want to use more strands of it, to keep it from sagging too much and drawing the individual strands too tight.

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Nice Job!

Post by abirdie4me » Tue Aug 19, 2008 7:48 pm

Nice work!

I only had 2 WD Raptors, so I suspended them like this:


I made major mods to this case, wore out quite a few dremel blades! I cut out all the fan grill in the case, even the bottom intakes. You can see the scythe slipstream fan laying on foam under the bottom Raptor, keeps them both cool. I have temp sensors on them, they average around 35 C under load.

Love this case, but love my P182 also.

If interested, I've started a build thread on this machine over in General Gallery:


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Post by oldabelincoln » Wed Aug 20, 2008 2:33 am

Where'd you find 1.8mm stretch Magic? Local craft stores in Silicon Valley don't stock anything remotely that thick.

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Post by SeanTek » Mon Jan 19, 2009 12:09 am

You can get them at Artbeads, and there is free shipping (at least right now). That is probably the most cost effective option. Just Google for Stretch Magic 1.8mm 3 meters.

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went with velcro

Post by cordis » Fri Mar 13, 2009 12:56 am

Well, I took a look at this, but I went another way. The elastic suspension looks good and all, but it does seem like a lot of work with tools and glue and stuff, and I couldn't find the elastic around. Ultimately I just picked up a roll of velcro at Home Depot (10' size) and took out some scissors and went to work. I wanted something to keep them off the metal, but allow them to be removed relatively easily. This system is where I'm sticking all my old PATA drives to hopefully die soon, so I'm not too worried about the shape they end up in. So what did I do? First off, I slapped on some loops on the outer edges:


then I made some long strips to go down the middle:


with some hooks on the bottom to hit the rails:


then I laid the strips into the slots:


prepared the drives with some hooks stuck on in strategic spots:


then you can just stick the drives in. Of course, they won't necessarily stand up straight:


but you may notice the little hook spots on the side. Connecting a cross strap gets them standing upright, and allows for a quick release when you want to remove them:


So, kind of cheap, but it seems to work, I sure can't hear the drives now. What do you think?

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Post by pcy » Fri Mar 13, 2009 4:47 am


We have just redisgned the HD cage in the PaQ cases to do something similar.

We use rubber O-rings which are very robust (lots of cars suspend their exhausts on thicker versions).

Each HD is suspened on two O-rings, each strung across one end of the HD cage. This is acheved with two pieces of plastic screwed onto either side of the HD using the normal side mounting holes: the plastic pieces have protruding hooks which hook over the O-rings.

The natuaral frequncy if the HD thus mounted is about 10-12Hz, way below the typical excitation frequenncy of 120 Hz (=7200 rpm).


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