Clever Substitute for "Poor Man's Audio Deske" ?

I noticed that CDs are not the same diameter when using my De Mat.
The small lip on the outer edge of the dampening mat does not lay flat on larger diameter discs.
I am trying to find a way to cut, shave or sand the outer disc edge by carefully mounting the CD in say, a small cordless drill at low rpms. (self-centering device with rubber) ?
I'd use a junk CD to start, so yes, I already know the risk factors involved with scratching or trashing my collection.
I only need to remove very little material.
What I don't want to do, is spend $ 500.00 + on the System Deske.
The PC layer protects the inner metalized layer from corrosion and oxidation. Cutting into that layer could allow moisture and other nasties into the metalized layer, which in turn will render you prized CD as a coaster.

Audio Deske is likely more interested in sell machines that looking after you discs.

I've stayed away from posting on this since I don't even do digital. Since it's going to drop out of sight without anyone saying anything I'll give you my take on what you want to do. I doubt very much if a self-centering device that is hand held will be accurate enough. As I understand it you need to control two things. First is the perfect outside diameter and second is the 38° angle on the CD edge. You could make such a device fairly easily within a good home shop but even if you had the experience I think it would take a fair amount of time to make it and have it be reliable and repeatable. After looking at the commercial unit that design is what you need. I doubt the parts would be expensive at all.

This device corrects a couple of areas I've felt needed to be dealt with bacause of rpm's of CD's. The one problem area that's not addressed, and I've posted about this before, is balancing of the CD. I've seen labels where the silk screen (if that's what they label with) ink is very heavy on one side and non-existant on the other. It must be like driving a car tire at speed with incorrect weights. I'd also guess that such a label is hard on the players mechanicals too.

A couple of the ears I trust here at Audiogon are having their CD's cryo'd in bulk at very inexpensive prices and are extremely happy. I bet I know someone that would send you a couple of CDR's where one is cryo'd and one isn't for you to audition. The success of this treatment has been double blind studied within this small group and they choose the cryo'd version nearly 100% of the time. Food for thought anyway.
Thanks guys, for having the "guts" to post on this !
Very interesting points brought up about balancing and the PC layer, I'll look into that.
I have been trimming my disks with the Audio Desk for three years. I have never had any problems with the 1000 cds and sacd I have trimmed.

I have a friend with a home solution for the Audio Desk. He uses his lathe, hardly a money saving solution for most of us.

The Audio Desk does not trim the disks to the same radius from center. It merely make the bottom half of the disk have a angle of 30 degrees I believe.
Rx8man: While not directly related to your question in terms of a "budget" Audio Desk alternative, i thought you might be interested in a couple of older posts of mine from AA on the subject. I've had mine for almost 5 years now with nary a problem from any of the discs that i've "circumsized".

My original Audio Desk Systeme Review from AA

The second link is from a thread where Jack Seaton mentions a friend that works for IBM testing various compounds / tweaks on CD and then testing for error rates afterwards. As mentioned, Jack and his buddy found that some treatments were detrimental and increased the error rates, yet he had no problems or second thoughts about using "the cutter" on his discs.

Various disc treatments and error rates

If you or someone else is interested, and much like i do with cable burning, if you send me your item and cover return shipping costs, i've got no problem with cutting some discs / burning cables. Those that are skeptics can experience the difference for themselves first hand for the cost of round-trip shipping. Sean
Hey thanks Sean, you're a super guy.
I've followed your threads closely on a lot of topics (tried to keep up) esp. on AC treatment.
I know there's another home-brewed solution for a cutter, I'm working on a simple method.