What would happen if you put a CD with a crack in it in the CD Rom?

Marc Lizer

SGF, Supreme Grumble Framer
Jun 28, 1999
North Hollywood, CA
I noticed a crack, starting at the center, and going about an inch.

So I was thinking: I should try and get the data off that, and get whatever is readable.
The data is written from the center ring out, so its unlikely the thing will be readable with a crack.

I know someone who did that in the past and the CD shattered into about 30 small pieces when it spun up to speed. I was the poor sucker that had to open it up and take out all the pieces

At the point when it made a sound the same an unabriged Websters dropped from 5 feet, I thought something was amiss.

When I opened the drive, apprehension was confirmed in a rather spectacular fashion.
Of course you realize that at least 37 people who read the Grumble are going to have to try this for themselves.

Ouch... (gotta laugh though).

In case anyone is wondering (like I was) how fast modern CDROM drives spin a CD, a 52x speed drive is approx 27,500 rpms. Which is somewhere in the neighborhood of 180 miles per hour at the edge of the disc.

I found a very informative site that experiments with CDs and a 30,000 rpm Dremel (they have movie clips and everything).
Very cool stuff.

Where he mentions the phenomenon of the data foil separaing from the surface was what I found most interesting.

Since my post, I took the drive out, and got a look inside.

Almost no data surface remains on any of the (former) disk surface. It looks that crack extended the width of the disk. The film of the data surface held the integrity of the failing disk, much in the way laminated glass holds a break complete shatter.

It would have broke at a lower RPM. But the film allowed it to get to full speed. Then the foil delaminated from the disk (and shredded into a billion glittery bits of data), and the flying broken disk bits (going very fast) traveled a whole 1/4 inch to the interior of the CD Rom box. And became even smaller bits of broken plastic.

There are dents in the metal.

Very cool. I would almost try this again on purpose.
How about the CD drive? What happened to it? My drive is deceased without ever haing put a disk in it. Touchy thing. Just like my car security system.
Yea the one I repaired was dead shortly after. They spin at an incredibly high speed. It actually made dents in the metal case? WOW