Wrong. Think about it this way. Start with a sheet of metal. Cut a disk out of it. The disk and the plate are the same material and the same coefficient of expansion. If you heat both pieces, the disk obviously gets larger.....but it's still got to fit in the hole...so the hole must get bigger! Jon Gus S Calabrese wrote: > When looking into the abyss of defeat, > change topics. Nice move , Tony > > > When a piece of metal is heated ....... > as temp approaches infinity, the hole gets smaller. > > > Gus > > > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist