Ron...

If you're scanning just chips and they're not in holders, I recommend that you turn your scanner upside down and just place the chips on the lid. This makes alignment virtually foolproof, since you are seeing the chips as they will be scanned, and not the backs of them.

A couple of warnings, however... this will only work if the scanner bed is pressed firmly against the chips (which is why this won't work too well if the chips are in enclosures), and it definitely will not work if you have items of different thicknesses (ie: matchbooks, chips, etc. all in the same scan).

Also, if you have the urge to flip the scanner right-side-up, fuhgeddaboudit... the chips will slide around.