like in this tutorial .http://www.youtube.com/watch?v=hJs4k-30rew

it seems to be hit and miss and never works ,the stages seem pretty simple but i can never get it to extrude as shown .

draw cirle

project onto outside face

convert entities

draw line to give direction of extrude

extrude in direction of line

but it just wont extrude as shown ,i get an error message