I am apparently missing something.
The paperstone base is 1-1/4″ thick and the mounting screws are 1-1/2″ long overall (1-3/8″ thread length-excludes the flat, countersink screw head). If I add the washer (metal/rubber) as I originally asked about, there is not enough male screw thread protruding from the top of the paperstone base to be able to engage the sharpener base female thread.
Surely I am doing something incorrectly.
Sorry to be such a bother, but…
Thank you.