I have had my bitzenburger for over 30 yrs and yes you can only do one feather/vane at a time. They are completely versatile (sp) in how much of a degree you may want but you have to specify left or right helical as mine is a left and is not campable of putting a right helical on. I have gotten my monies worth out of mine is is a very good choice. Bobby

>>>>>>---------PROUD MEMBER OF THE ELITE 8------------------>