Phil:
Have a look at these portable storage boxes from Craft Supplies - available in 2" and 3" sizes:
Sanding Disk Storage Boxes
You can often find these kinds of boxes at sporting goods stores near the fishing tackle. Our local Walmart has a pretty good selection; so does Hobby Lobby (near the painting, beading, jewelry kit supplies), as well as our local sporting goods store (near the fishing lures and other small tackle - you may even find a fishing tackle box that will do the job). Alternatively, they occasionally sell similar compartmentalized boxes at hardware stores for screws, nuts, bolts, washers, etc. I use several of these kinds of boxes for various collections of related turning tools (i.e. 3M bristle sanders, Morse collet set, Joyner pendant jig, penturning kit, etc.) and they are very handy when you need to travel to do demos and have all related tools, parts, adapters, etc. all in one place. Many have adjustable slots to allow you to customize the box for your purposes.
I admonish you to check the quality of the hinges before you buy these boxes - some are just thin, bent parts of the molding that attaches the lid to the bottom - these "hinges" often wear out and break fairly easily during repeated use, and are a waste of money. Others (such as those by Plano) have true 'pinned' hinges that last a long time. The extra cost initially is offset by the generally long life, and no need to replace a cheap box. Take discs and holders of the size you intend to use with you to the store so you can check the fit of the compartments before you make the purchase - don't ask me how I know that....
Been there, and have bought these many times...
Rob