Jeff Wisnia wrote:

....

Thus, a pile of cannonballs and a rack say 4 feet on a side dropping in
temperature from say 70 F to -20 F would have an overall differential
length change of

4 * 12 * 4e-6 * 90 = 0.017"

Now LLoyd, please tell the group what you think that rack must have
looked like, and just how seventeen thou of change in a four foot long
dimension made the balls fall off it.
....

Must have been those tight tolerances...