in the section starting with page 85 with Tull narrating, Why does vernon mention Cash's carving plugs for the holes in the coffin?

The care Cash takes with the coffin is mentioned in both parts one and two of the text. In part two, Vernon hopes that Cash takes as much care with the barn he's supposed to build, it part three Cash is once again meticilously completing the carved plugs.

Outside of the fact that both of these citings seem to reflect on Cash' pride in workmanship, I don't really see a reson for mentioning them. Cash is being portrayed as a craftsman who takes immense pride and care to details in his work. Thus, these descriptions give us a intimate look at Cash himself.