Calliope,

The first time I cleaned my pasta machine I thought I broke it because
I put it back together wrong. The sharp edges do point towards the
center and fit snug up against the roller - that's what forces the clay
away from the roller and down the slot in the center. If you put the
scrapers on backwards the clay doesn't release from the roller but goes
right past the scraper and into the machine (what a mess!).

Laura Campbell
(new to the group and loving all the information here!)