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Hardware

Investigating Angular Velocity 271

Posted by michael from the young's-modulus dept.
mbreitba writes "Sam Barros is at it again, Some may know him for his Railgun research, and some may know him for his homemade cannons. But now he's found a use for all those old CD's you don't need anymore. Personally, I couldn't think of a better use for them."
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Investigating Angular Velocity More

Investigating Angular Velocity

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  • they've been lying to us (Score:5, Funny)

    by gfody ( 514448 ) * on Wednesday June 11, 2003 @03:41AM (#6168776)
    52x isn't the max its 172x!
    I don't care if the cd could come out of my burner fly across the room and explode into a billion pieces, I wanna 172x burner!

    seriously though, why do they only try to spin the cd faster. why not spin the laser in the opposite direction the cd is spinning in?

    • Re:they've been lying to us (Score:4, Interesting)

      by Cryptnotic ( 154382 ) on Wednesday June 11, 2003 @03:49AM (#6168802)
      How about multiple lasers, each reading/writing simultaneously?

    • Re:they've been lying to us (Score:5, Insightful)

      by inaeldi ( 623679 ) on Wednesday June 11, 2003 @03:56AM (#6168834)
      why not spin the laser in the opposite direction the cd is spinning in

      Too expensive, and for what? Is a CD burned in 3 minutes not fast enough for you? Would you be willing to pay 4x as much to burn a CD in only 1.5 minutes?

      • Is a CD burned in 3 minutes not fast enough for you?

        hell no its not fast enough.. if I wanted to make a backup of my cd collection at 3 minutes a disc it would take me a week! I dont know about paying 4x as much for 1.4 minutes but let the market decide that one.. don't decide 3 minutes should be fast enough for everybody. If there was a burner that could burn a cd in 5 seconds I'm sure there are plenty of people willing to pay a premium for it
        • So just buy another CD burner and burn 2 CDs at once. If you want to go really heavy duty, get a rack of 8 SCSI burners or something. It'd probably still be cheaper and more economical than a spinning laser that has to automatically re-focus every microsecond (or whatever).
          • why so content on waiting 3 minutes for a cd to burn? do you use a 486 cpu that takes 3 minutes to start your aol too? is it not cost-effective to upgrade to a faster cpu, you would rather have two 486's each take 3 minutes to load 2 aols?

            seriously, sometimes you can split the task into parallel tasks and use multiple units to scale horizontally but in the end it still takes 3 minutes to burn a cd! 3 minutes is a long time when your in a hurry. also, if it takes a scsi tower with 32 burners at 48x to burn
            • If they could figure out a way to burn CDs faster and at the same time do it cost effectively, then that'd be fine. Your parallel to CPUs is faulty. CPUs are not limited by a physical impossibility (that we've reached yet anyways). Making a faster CD burner isn't just a matter of finding ways to cram more and more transisitors in.

              ...I don't use AOL.

            • Arguing for the sake of arguing... (Score:5, Informative)

              by lenski ( 96498 ) on Wednesday June 11, 2003 @08:21AM (#6169749)
              Heelloo, This is *slashdot*! Arguing for the sake of arguing is "our" stock-in-trade! :-)

              Unable to resist...

              Ye olde "9 pregnant women having a baby in 1 month" argument... For another analogue that may apply here, it's worth noting that recent developments in semiconductor processing technology includes a move to 30cm wafers, specifically to accommodate parallelism in production.

              I don't remember the dates specifically, but silicon production "began" with 3-inch wafers, then transitioned to 5-inch, then 8-inch. So, don't be too harsh on those who suggest doing things in parallel.

              Producing 1000 CDs per day? Consider standard pressing techniques, which is nearly as flexible as "burning" CDs but way cheaper and can be performed as quickly as you wish. (Did you know that CD sputtering chambers can contain multiple different blanks?)

      • Hmm how about a small spinning/moving lens+prism with a fixed laser and disc. Much less moving parts, you just need to make that focusing device ultra tough and fast and everything else can sit there without experiencing much stress...
        • And able to sustain the impacts of shards deflected off the shoddyly manufactured cheap disks as the shatter in your drive...I've had lables come off at regular speeds. (j would second this.) PNY media NEVER goes in my drives anymore.

          Actually, now we have something to do with all the frisbies and AOL cd's/cup coasters we've been saving over the years, dont we.

          I'll bring over my dremel this weekend. :)
      • I think I paid 4x as much for my 2400 baud modem then my 1200 baud modem. I was using an 8-bit computer at the time, so my average transfer time was 3min under 1200 baud, and 1.5min under 2400 baud.

        Besides, 4x as much is pretty much the diffrence between a $50 CD-r and a $200 CD-r... what I get for the ide units on www.pricewatch.com and based on shopping at office depot.

        If you honestly could build a CD drive that employed the use... to make things simple here.. a stationary disk and a spinning laser rea
    • seriously though, why do they only try to spin the cd faster. why not spin the laser in the opposite direction the cd is spinning in?

      You mean something like this [trygve.com]?

    • Multi-beam Kenwoods are where things were supposed to go. 7 beams, faster reading, and a much lower CD speed. Unforunately, they screwed up compatibility, and there was a much longer initial access time.

      You can find a little info on them here [pcstats.com].

      I have a 52X that still works well. Quietest freakin' drive I've ever used.

    • Similar thing is being developed in the "holographic memory". You don't spin the laser, just a tiny mirror that can turn VERY fast and move up/down at "reasonable" speeds. The media is not a disc, but a drum though (actually: A roll of duch tape), it stores 1TB of data and doesn't move in the process. The mirror is located in the middle and focusing the laser makes it possible to read/write any point of the media volume, not just the surface.
      • > You don't spin the laser, just a tiny mirror that can turn VERY fast [...] The media is not a disc, but a drum

        That's an amazing idea. Do you know any names of companies that are working on that? Or where more information could be found?
    • A far better idea is to have 4 seperately moveable heads to quad the read speed. That will also help a lot in random seeks.

      Come to think of it, its possible to have a tiny moveable mirror reflect the laser around in circles on the CD. A parabola-like reflector beneath the CD can direct the laser and the read data with only the little mirror being moveable and the CD being stationary. I think it will fit in one drive bay, and can be completely financially feasable.

  • yawn (Score:5, Funny)

    by Anonymous Coward on Wednesday June 11, 2003 @03:44AM (#6168782)

    Copyright © 2002 by Sam Barros. All rights reserved. Removing any material from this site for display without consent from its author consists in an infringement of international copyright laws and can result in fines up to $50000 per infringement, plus legal costs. So ASK ME before you remove anything from here.

    Oops, if anybody visited the site and it was all blank, sorry, that was me after I removed his content! I'll put it right back.

    I love reading all the different ways people threaten in their copyright notices.

    But wasn't a better version of this concept posted here like last year? A guy put the CD in a real high-speed, high-torque moter (not a dremel) and watched it shatter on the spindle.

    This guy is just spinning them fast on a dremel tool and watching them shatter when they hit the ceiling, not quite as impressive!

    • Reminds me of the time I was trying to make a centrifuge, and I thought it would be good to test it first by mounting a Frisbee to the motor. I was using a 1 hp Alcatel vacuum pump motor (~30,000 rpm) in a vacuum (about 1E-3 torr). The Frisbee disintegrated nearly instaneously. I was picking little pieces of purple plastic out of the vacuum chamber for the next hour.
      I decided not to build that centrifuge. Hmm, chunks of steel at 1800 km/hr... It was just a little too scary for me.
    • So is making a mirror of the site okay? Or do you mean "copying any material for display"? Uh oh, I just downloaded it, and Opera is displaying it..

  • Already been investigated.. (Score:5, Informative)

    by DeathOverlord3 ( 645635 ) on Wednesday June 11, 2003 @03:46AM (#6168789)
    turns out most cds explode at 28k rpm according to this [slashdot.org] story from a couple years back. and even then it was a dupe.

  • Either do that... (Score:5, Informative)

    by stere0 ( 526823 ) <slashdotmail@stereo.CHICAGOlu minus city> on Wednesday June 11, 2003 @03:47AM (#6168790) Homepage
    ... or put 'em in the microwave for a couple of seconds, shiny side up. Put a sheet of paper below if you don't want to stain the glass plate.

  • mirror (Score:4, Interesting)

    by Barbarian ( 9467 ) on Wednesday June 11, 2003 @03:48AM (#6168794)
    I have a full copy of that page, with the videos, but no way am I mirroring when the author of the page threatens to sue for $50000 at the bottom.

    • Re:mirror (Score:2, Funny)

      by realdpk ( 116490 )
      Just don't remove the content and you'll be OK.

    • Re:mirror (Score:2, Informative)

      by Anime_Fan ( 636798 )
      For us mere mortals, not even that is possible... He seems to be slashdotted already...

      But according to this (another slashdot comment), you have violated his notice (removing any material), if you were planning on displaying it (doesn't say anything about public showing), so I GUESS YOU'RE SCREWED (or not):
      Copyright © 2002 by Sam Barros. All rights reserved. Removing any material from this site for display without consent from its author consists in an infringement of international copyright l
    • Alow me to quote my favorite still [hillnotes.org], from his good CD explosion. It's an amazing and frightening image, in which we can clearly see the trajectory of a large chunk many frames before the author had time to flinch. I'd like to see a pciture of his ceiling where much of the energy may have been deposited.

      I'd also like to share a sad story of a lab death due to flying glass. Somewhere around 1989, a student at Tulane died when a piece of glassware exploded in his hand and a fragment severed his jugular ve

  • why spin the CD at all (Score:5, Interesting)

    by Anonymous Coward on Wednesday June 11, 2003 @03:49AM (#6168799)
    I bet in the future, you'll be able to get "legacy" CD-ROM drives that just take an optical image of the whole disk once, load the content into a buffer, then eject the disk, in about 5 seconds.

    That would be cooler than 12,983x drives.

    • Re:why spin the CD at all (Score:2, Interesting)

      by BJH ( 11355 )
      I seem to recall some company made something similar to this - a CD-ROM drive with a built-in hard drive, where the content of the CD was cached on the HDD to allow quicker access.

      This would have been quite a while ago. Anybody else remember these?
      • I seem to recall some company made something similar to this - a CD-ROM drive with a built-in hard drive, where the content of the CD was cached on the HDD to allow quicker access.

        This would have been quite a while ago. Anybody else remember these?

        Yes. I used to work in a small computer store. These 'wonders' were also sold w/o their own hard drive, as 100x cd-readers.
        What they did is spend about 10 minutes staging when you put a new cd in, making an image of it on the hard drive, but telling your PC th

      • This would have been quite a while ago. Anybody else remember these?


        Sadly, yes. I used to be a developer for one of the companies that did those...

        Seems like they even made it into production:
        http://www.axis.com/products/cd_dvd/i ndex.htm

        Not that we were the only company that made those...

    • [cnn.com]
      This article from CNN makes mention of such a thing coming from Sony.

      The range also features a CD audio system in which a disc can be placed anywhere on a playing surface the size of a salad plate.

      sounds incredibly cool! but it's part of Sony's megathousand dollar line of products in development. Im not sure what it is or how it works, or even if its close to the idea. This is the only place ive ever seen mention of this thing.

      sounds pretty cool though!

  • Whooopie (Score:4, Funny)

    by Zork the Almighty ( 599344 ) on Wednesday June 11, 2003 @03:49AM (#6168800) Journal
    Whoopie, another story for Power Labs. What's their slogan again ? "We know just enough science to wreck something, then we call it an experiment."

    • Re:Whooopie (Score:4, Funny)

      by IntelliTubbie ( 29947 ) on Wednesday June 11, 2003 @03:53AM (#6168821)
      Whoopie, another story for Power Labs. What's their slogan again ? "We know just enough science to wreck something, then we call it an experiment."

      If that's the case, we're doing a damn impressive experiment on their web server. Yee-haw!

      Cheers,
      IT

  • AOL (Score:4, Funny)

    by Zelph ( 628698 ) on Wednesday June 11, 2003 @03:49AM (#6168803) Homepage
    Dang! Where are all those AOL CDs when I actually WANT them?

  • Freeze the CD... (Score:5, Insightful)

    by Max Romantschuk ( 132276 ) <max@romantschuk.fi> on Wednesday June 11, 2003 @03:50AM (#6168806) Homepage
    From the site:

    A standard compact disk has a diameter of 12cm. If this disk is to spin at 35000RPM, the peripheral velocity at the edges of the disk (.377m circumference x 583.3 turns per second) will near 220m/s, or 722fps, or 792km/h or 492miles per hour. That is one fast CD-Rom!

    At those speeds the CD is storing over 150joules of energy.

    I wonder if Freezing the CD would make for even more spectacular explosions... after all the speed and energy stored in the CD is really ridiculous.

    Freezing usually makes most things more fragile, right?

    • Re:Freeze the CD... (Score:4, Informative)

      by bn557 ( 183935 ) on Wednesday June 11, 2003 @05:06AM (#6169014) Homepage Journal
      How temperature affects the properties of a material are intrinsic to the material. Examples: Water becomes more rigid when you freeze it. Silly Puddy becomes hard when you freeze it. But with plastics, yes they generally lose their ability to bend without breaking. It raises their resistance to change, which raises the stress in the material at a given amount of bending. That leads to it breaking.

      P
    • CDs are already frozen; freezing is the act of making a liquid a solid...

      freezing things such as flowers in liquid nitrogen works by freezing the liquid water already in the flower, making them brittle.

      However, if you've ever broken a plastic ice tray that's been in the freezer, you know that plastics are more brittle at lower temperatures... but it's not freezing.

  • Trashed (Score:2, Funny)

    by Mattygfunk1 ( 596840 )
    Spinning CDs with a drill eh?

    Actually it probably makes sense considering he also has a "Chemlabs" page he was probably stoned at the time.

    __
    Cheap Web Hosting [cheap-web-...ing.com.au]

  • Jackass for geeks (Score:5, Funny)

    by shaneb11716 ( 451351 ) on Wednesday June 11, 2003 @03:52AM (#6168816)
    'nuff said.

    -Shane

  • Pointed Out Already (Score:4, Informative)

    by OverlordQ ( 264228 ) on Wednesday June 11, 2003 @03:52AM (#6168817) Journal
    This is a dupe of this [slashdot.org]which was a dupe, funny that. Here is a mirror of it (the first dupe), since the site was taken down: My Mirror [thedarkcitadel.com]

  • Hmm... (Score:5, Funny)

    by rgoer ( 521471 ) on Wednesday June 11, 2003 @03:53AM (#6168818)
    Guess I should call Big Broth^H^H^H^H^H^H^H^H^H Ashcroft at T.I.P.S. to let them know that AOL has apparently been engaging in some very suspect "terrorist-like" activity, filling my mailbox with potentially dangerous explosives for years.

  • How do we know how fast it was spinning? (Score:5, Interesting)

    by anubi ( 640541 ) on Wednesday June 11, 2003 @03:53AM (#6168819) Journal
    He notes using a dremel tool to spin the disk.

    He also notes the disk speed is lowered due to aerodynamic drag.

    Personally, I would have been impressed if he had done something to the disk, maybe going over quarters of it with a black felt pen so an optical pickup could have determined its RPM, instead of guessing.

    At those speeds, gyroscopic effects can really be exaggerated! Gyroscopic effects alone can result in some really bizarre behaviour when the plane of rotation is changed.

    This experiment reminds me the time we got a flywheel spinning off the table-saw motor in high school shop. The flywheel got away from us when unexpected gyro forces wrenched it from our hands. The damage that thing did was talked about from then on to beyond the day I graduated.

  • While watching the movie... (Score:5, Funny)

    by Flounder ( 42112 ) * on Wednesday June 11, 2003 @03:59AM (#6168845)
    was just waiting for a perfect example of why you should always wear eye protection when doing something extremely dangerous at extremely high speeds.

    You'll shoot your eye out!

  • Other good uses for CDs (Score:5, Interesting)

    by dew-genen-ny ( 617738 ) on Wednesday June 11, 2003 @04:01AM (#6168850) Homepage
    A few years ago, myself and a friend found another, equally interesting use for old CDs:

    You can use a stack of them hooked up together as a big high-voltage capacitor!

    We connected them all up, then passed in ~20K volts, and it really could hold it's charge (I can't remember the numbers - since then, I've lived in amsterdam for 3 years, and a'dam tends to have a negative effect on ones memory....). What was amazing was when you hooked it up to the powersource, all the disks were attracted to each other and clamped up really tight.

    Discharging the thing was amazing, and the 'zap' (for want of a better word) could easily burn through some thick paper...

    Maybe when I've got some time I'll repeat the setup, this time with some photos, then I'll enjoy a good ol' fashioned slashdotting...

  • Full Text... poor server... (Score:5, Informative)

    by SJ ( 13711 ) on Wednesday June 11, 2003 @04:06AM (#6168865)
    Have you ever loaded a faulty CD into a high speed (30X or higher) CD-ROM player, heard it spin up to incredible speeds, rattling and whining, and thought to yourself: "this thing is going to explode"? When CDs came out they were heralded as the solution for the need for high storage-high speed information devices, transferring data at a whopping 150kb/s, but like all technologies, 1x CD players quickly became obsolete as the need for higher and higher transfer rates pushed for faster players, and, with them, higher rotational speeds. As we advance into the 21st century CD players are reaching the ultimate speed limit: we are getting to the point where the CD player simply can not spin the CD any faster or else the CD will literally fly apart. On the interests of the advancement of high speed computing PowerLabs brings to you:

    THE ULTIMATE CD SPEED LIMIT!
    WARNING: This page is written for amusement only: These experiments are VERY hazardous!; A high speed rotating CD Rom is a bomb ready to explode and will send razor sharp plastic shrapnel in all directions when least expected. DO not attempt to replicate any of the experiments described below!

    Setup:

    Before an experiment could be devised where a CD would be rotated to complete failure, a proper motor had to be obtained that would be capable of achieving those high rotational velocities with the load presented by a CD. Although a CD is very light and aerodynamic, when it starts to spin at a couple tens of thousandths of rotations per minute the drag created by air around its surface can be to slow the motor down considerably. High torque motors are very common and cheap, as are small high speed motors. Unfortunately however, high speed, high torque motors are a much rarer and expensive find.

    My choice was to use a Dremel tool as the motor. It was cheap, easily available, and, more importantly, the rated 35000RPM spindle speed meant that it had some real potential for spinning things to destruction.

    At 35000RPM very small imperfections and balancing errors can lead to extreme vibration; so much, in fact, that it would be possible to damage the bearings or bend the axle on the tool if something as heavy as a CD was to start wobbling (bear in mind that the Dremel tool was designed for very small, light weight loads and even then many of its attachments carry warnings not to be used at full speed). One of the first challenges of the research was to find a means to secure the CD perfectly in the middle of the tool. A custom made CNC lathe spun aluminum holder was considered but before I ever left the room I realized that the cylindrical sanding attachments Dremel makes not only fit a CD hole perfectly, but also have adjustable width so that the CD could be gripped in place. With the CD in place and the dremel plugged in, it was time for the fun to begin!

    The Dremel was switched on and the rotational velocity was gradually increased to its maximum, at which point the CD hummed and whined in a very menacing manner. Mildly disappointed that it had not exploded, I realized that it wanted out; a quick jerk at the tool and the CD slid out of the holder and contacted the carpet whilst spinning at ungodly speeds. It peeled out a bit in front of me and proceeded to make its way to the door at a very high speed. On contacting the closed door, the CD did a most unexpected thing: it first bounced back a few inches, and then, when it hit the door again, it jumped straight up the door and struck the ceiling, exploding into thousands of fragments which rained down on the entire room. This first experiment was unfortunately not videoed, but it served to get everyone in the room to put glasses on and cower away behind pieces of furniture, whilst people in the hall corridor quickly made their way to my door to ask what was going on. Now, with an audience, the camera was taken out and the real experimentation began...
    ÂA standard compact disk has a diameter of 12cm. If this disk is to spin at 35000RPM, th

  • This guy is going to get pissed (Score:5, Funny)

    by Playboy3k ( 552242 ) on Wednesday June 11, 2003 @04:19AM (#6168907)
    Last time this happened his site was slashdotted and consquently due to bandwith caps wasnt up till 3 weeks later. Wait till he finds that he has been put on the front page again. Better start looking behind our back's for some guy with a dremel and a couple of AOL cd's.

  • Here's a quote from the manual of my CD-RW drive:

    The PlexWriterâ(TM)s reinforced tray bezel and drive bezel can resist the escape of the disc or disc fragments in the event of disc failure at this high 48X speed.

    I knew it was worth paying the extra for the Plextor. Although such an event would almost certainly wreck the drive, it would still be a pretty cool story.

  • This picture is priceless (Score:5, Insightful)

    by Anonymous Coward on Wednesday June 11, 2003 @04:41AM (#6168952)
    This [powerlabs.org] picture is great. The guy is sitting on the floor looking at a 35000 RPM CD which is most certainly going to explode, and wearing nothing but a pair of (what looks to be) sunglasses! He looks like a little kid whose found his first book of matches and is mesmerized by fire! I can't view the video (./'d) so I can't comment of his actual procedure, but from the looks of things he could have been in for a world of hurt. At 35000 RPM, that plastic might as well be concrete, or glass.
    • > from the looks of things he could have been in for a world of hurt.

      Well, as long as the Dremel is kept pretty still, all the exploding fragments will move outward, in a circle, from the bit. As long as his POV was perpendicular to the CD, he should be safe from being immediately punctured. Of course, shattered CD parts bouncing off of nearby walls is another matter entirely.

    • Definitely. Why are these guys wearing sunglasses? To look cool probably. The protection effect against high-velocity CD fragments is negligible. Still, it might help against secondary hits, which bounce off walls. The primary shrapnel goes off radially, so you can control it pretty good.

      Anyway, these people seem to have too much time on their hands :-)

  • From the blog of Sam Barros... (Score:5, Funny)

    by ites ( 600337 ) on Wednesday June 11, 2003 @04:43AM (#6168956) Journal
    Tuesday, 5am.

    I keep having these dreams about things exploding. Tonight it was my microwave. I filled it with AOL CD's, set it to 'Aggressive Defrost', and sat down with a beer. The explosion took off the roof of my house and sent it into space. This dream gave me another great idea I can't wait to try: sending cargo into space by blowing up AOL CDs.

    Wednesday, 7pm.

    It did not work. The neighbour wants back his microwave, and my son is asking me where his music collection went to. Well, that's one positive angle, anyhow.

    Thursday, 5am.

    That dream again. My subconscious is trying to tell me something. Maybe I was using the wrong brand of microwave...

    Friday, 8pm.

    I think I've cracked it. Instead of just one microwave, you have to imagine a Beowulf cluster of the things...

  • Page counter (Score:4, Funny)

    by Rosco P. Coltrane ( 209368 ) on Wednesday June 11, 2003 @04:46AM (#6168966)
    Look at the counter on the guy's page : it has only 4 digits. How much do you bet it already rolled over a hundred times ?

    I can just picture the guy in trance mumbling "no, no, I'm not slashdotted, my server isn't smoking, it can't be, I only have 4000 hits so far ..."

  • Here's the MPEG (Score:5, Funny)

    by SEWilco ( 27983 ) on Wednesday June 11, 2003 @05:32AM (#6169068) Journal
    For those who can't get the MPEG video from the site:

    0000000 0000 ba01 0021 0001 8001 5d16 0000 bb01
    0000020 0c00 1680 055d ffe1 e0e0 c02e 20c0 0000
    0000040 be01 dc07 ff0f ffff ffff ffff ffff ffff
    0000060 ffff ffff ffff ffff ffff ffff ffff ffff
    *
    0004000 0000 ba01 0021 0a01 8031 5d16 0000 e001
    0004020 f307 2e60 0031 9601 1107 0100 917e 0000
    0004040 b301 0014 c4f0 ffff b8e0 0000 b801 0880
    0004060 4000 0000 0001 0f00 f8ff 0000 0101 f96b
    0004100 19ee 4cc7 5b59 835a f211 55fe 3761 f1f4
    0004120 5c46 bd6b 9624 0f52 6aed 4c33 6ecd d3fa
    0004140 4ad5 78f5 93b2 72db 5375 c5c0 e386 3f6b
    0004160 9225 8e50 ef2c 8677 86f9 7fa4 71b5 2357
    0004200 9c55 19ac 9fb3 5ddc 1878 cc1c dc3a 8f37
    0004220 0df2 bb48 8d4e b6cc 114a efd9 03a0 ca1d
    0004240 4ae8 1003 ef91 59bf d78e 0911 d2e4 9190
    0004260 608b 6caf 2903 721f 4b90 232f 9d6f 5277
    0004300 1143 a8c7 ce5d 8c80 f4da 9824 db82 3ff4
    0004320 15b1 56d2 7f64 eb83 bc9c d007 84aa f912
    0004340 38c3 b97e f6d1 4fdb edef 2fb9 faac 90d0
    0004360 ae25 4b5f 8f14 bff1 e970 f751 dfb9 ad0e
    0004400 fbb8 b2ed e179 ea84 56d2 5004 155c 8d78
    ...more of the same

  • Newbies (Score:3, Funny)

    by Vihai ( 668734 ) on Wednesday June 11, 2003 @05:53AM (#6169120) Homepage
    I did it more than one year ago with a friend of mine, we actually managed to put the disc on the floor spinning at 15K RPM and making it run across the office at high speed for 50+ meters.

    We used a pencil to push the disc away from the dremel, if we had to force it for more than a fraction of seconds, the pencil would smoke :)

    At the highest speed the disc exploded (well... it was already damaged, we almost knew it would) and some SMALL piece is still stuck in the roof...

    Don't do this at home!

    (do it at the office :))
  • From the article:

    ...when it starts to spin at a couple tens of thousandths of rotations per minute...

    Just how fast is "a couple tens of thousandths of rotations per minute"??

  • St Anger (Score:2, Funny)

    by MixMiesterT ( 672651 )
    Now I know what to do with that new metallica cd. *shudders* damn that saint anger
  • Anyone else remember this game? You had a gun that shot CDs. IIRC, there was an Aerosmith soundtrack.
    • No no, the original poster was correct. The game was Revolution X; not only did Aerosmith provide the sountrack, they were (in some twisted fashion) the protagonists of the game's storyline (as such).

      The idea was that anonymous bug-eyed thugs in bad ninja costumes has, for reasons unknown, decided to deploy a huge army whose goal was to enslave everyone -- or perhaps just outlaw rock 'n roll, I was never too clear on this point. The hero (the player) had to blast his way through levels full of these guys a
  • The dremels head should be made to be somewhat conic, with the CD sitting on it. Sandpaper is fine around the cone, but should be something with a grip.

    And the whole structure should be built on a trolley and two columns where one column carries the trolley and the other touches and pushes the base of the CD at one end. Big rubber bands can hold the trolley holding the dremel and CD with a latch, and once the CD is doing well at high speeds, release the latch to fire the trolley and watch the CD disconnect

  • CD's (Score:2)

    by jefu ( 53450 )
    On a related note, what is the best way to cut (physically) CD's ?

    I'd like to build a few hanging geometric things out of CD's and have not yet found a good way to cut them reliably and accurately. I've tried various kinds of saw, craft knives and the like, hot objects, scoring and bending till they break and so on. Getting a couple good cuts is easy - getting a bunch of accurate shapes is a bit tougher.

    • Re:CD's (Score:2, Informative)

      by Abm0raz ( 668337 )
      The secret to carving CDs is to go slow and insure the rigidity of the CD.I find that by using contact cement and gluing a piece of 1/8" plywood to the BOTTOM of the CD, I can use a band saw on a CD quite well. The wood prevents the CD from bending, which will cause it to catch and crack/shatter or chip. I've also found grinding wheels to work well, too ... but the same thing, you need to attach something rigid to prevent the CD from bending. I find plexiglass to work well, too.

      -Ab

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