1 in l5 to 1 in 10

1 in 24 to 1 in 20

1 in 32 to 1 in 24

1 in 48 to 1 in 24

Acme threads

Square threads

Buttress threads

Multiple threads

5 times

10 times

15 times

20 times

small overall dimensions

accuracy of shaft alignment

low starting and low running friction except at very high speeds

all of the above

brittle materials

ductile materials

plastic materials

non-ferrous materials