brittle materials

ductile materials

elastic materials

plastic materials

spindles of bench vices

railway carriage couplings

feed mechanism of machine tools

screw cutting lathes

0.5 to 1

1 to 2

3 to 5

5 to 10

helical spring

conical spring

flat spiral spring

volute spring

friction angle is less than helix angle

friction angle is more than helix angle

friction angle is equal to helix angle

efficiency of screw is 100%