Regular Sewing String instead of Elastic to suspend HDD??

brianLp518 · Post by **brianLp518** » Mon Aug 30, 2004 12:18 pm

I was wondering if the elastic that everybody is using to suspend their HDD's has any more benifit that just tying regular string (i.e. sewing or kite string) around the screws of the HDD, and tying the ends of the string to the bottom of the 3 1/2 floppy cage to keep the HDD in the bottom of the cage and in the path of an intake fan. I wouldn't imagine that string would conduct vibrations to a major extent. I might try it out just to experiment.

rtsai · Post by **rtsai** » Mon Aug 30, 2004 12:31 pm

I know there's been plenty of discussion about this, but I don't recall anyone actually experimenting, simply because many people report success with elastic / StretchMagic / whatever other material is very cheaply available (less than $3 for all you'll ever need).

If anything, I would speculate that sewing string would be more prone to breaking, just because it is thinner. Probably not true of kite string / piano wire / assassin's garotte / any other material.

The advantage to the "normal" kind of suspension (as illustrated in one of the SPCR articles) is that you can actually move the case, turn it on its side, etc., with very little worry; the drive will just "hang" in whatever orientation the case happens to be in. With any other kind of one-sided suspension (it sounds like you're proposing to simply "hang" the drive from the bottom of a 3.5" cage), you'd have to be much more careful when you transport the case.

Post by **MikeC** » Mon Aug 30, 2004 1:14 pm

If it is not stretchy, it won't work. Wire, string, anything does not stretch/squish will have very little mechanical decoupling effects.

As for the longevity of sewling elastic, I've yet to see a single HDD suspenion made from this break on me. The earliest one goes back 2.5 years -- and it's still in use in my main rig.

brianLp518 · Post by **brianLp518** » Mon Aug 30, 2004 1:48 pm

I can image by suspending a HD by string would infer less vibrations than even the elastic would. The string would be allow to oscillate at nodes, and therefore, dissapate any energy transfered to it. The string vibration would not be transfered to the case. the elastic on the other hand, although having dampening capabilities, would not oscillate in the same manner, and transfer its vibrations to the case, no? I'm probably just being a dork.

Post by **MikeC** » Mon Aug 30, 2004 2:24 pm

Just try it -- the string does not work at all in comparison to elastic.

brianLp518 · Post by **brianLp518** » Mon Aug 30, 2004 2:35 pm

have you tried it?

alleycat · Post by **alleycat** » Mon Aug 30, 2004 6:52 pm

Brian, I strongly recommend that you take Mike's advice. Not only is he an expert in these matters, but from my own experience I can tell you that HD vibration is extremely insidious and you will need to use something which can absorb the vibrations. Or you can learn the hard way...

greeef · Post by **greeef** » Mon Aug 30, 2004 6:54 pm

brianLp518 wrote:I can image by suspending a HD by string would infer less vibrations than even the elastic would. The string would be allow to oscillate at nodes, and therefore, dissapate any energy transfered to it. The string vibration would not be transfered to the case. the elastic on the other hand, although having dampening capabilities, would not oscillate in the same manner, and transfer its vibrations to the case, no? I'm probably just being a dork.

The vibration of string is very very mechanically weak in comparison to the vibration caused by the hard drive. This means you would need yards of string to dissipate the vibrations caused by the hard drive. In a computer case, the string would serve only to conduct vibrations to the case.

Elastic relies on damping as opposed to destructive resonance... The movement of the hard drive is isolated to the hard drive and that alone. I have a suspended drive and a drive sitting on foam - the suspended is quieter.

griff

HammerSandwich · Post by **HammerSandwich** » Mon Aug 30, 2004 8:02 pm

A suspension is a low-pass filter. More give in the system allows isolation to a lower frequency. Think about car suspension. Softer springs provide more isolation from bumps.

meglamaniac · Post by **meglamaniac** » Tue Aug 31, 2004 6:08 am

But make you seasick when you go over a really big one.

Steve___ · Post by **Steve___** » Tue Aug 31, 2004 7:05 am

I think you may as well use elastic as it's virtually free, and will definitely be better.

However, I think inelastic string will work better than a few people think, as it won't transmit any vibration in the sideways planes, so even if it transmits all vibrations undamped to the case in the up-down plane, it's still removing 2/3s of the vibrations. Difficult to explain without a diagram but hope that makes sense

HammerSandwich · Post by **HammerSandwich** » Tue Aug 31, 2004 9:56 am

meglamaniac wrote:But make you seasick when you go over a really big one.

That's bad damping, not soft springs. But I agree; my father had an '81 Cadillac which was just AWFUL.

pangit · Post by **pangit** » Tue Aug 31, 2004 9:52 pm

HammerSandwich wrote:That's bad damping, not soft springs. But I agree; my father had an '81 Cadillac which was just AWFUL.

I thought all American cars have crap suspension?

(cue instant torrent of abuse.....

)

HammerSandwich · Post by **HammerSandwich** » Tue Aug 31, 2004 11:10 pm

pangit wrote:I thought all American cars have crap suspension?

Why do you think everyone here drives a truck?

brianLp518 · Post by **brianLp518** » Wed Sep 01, 2004 1:16 am

i drive a camry. =)

i tried using the sewing string.... Doesn't transfer ANY vibration to the case due to the small amount of surface area i guess. just tied a lasso loop around the 4 mounting screws, and lasso tied those the floppy cage.

Regular Sewing String instead of Elastic to suspend HDD??

Regular Sewing String instead of Elastic to suspend HDD??

Physics wise

Re: Physics wise