That is because they use a thick, drill-like spiral to create enough friction to pull the cork. This heavy spiral can easily crumble a tight cork--and often does.
The Wing Machine® overcomes this problem with an ultra-thin, non-stick spiral that moves through the cork almost frictionless. When the cork is fully penetrated, an automatic gear shift locks the spiral in place. Then the wings are pressed down, easily removing the cork--damage free!
And the whole smooth-as-silk operation of The Wing Machine is visible inside its transparent body. More than an innovation, The Wing Machine is a revolution in wing corkscrew design.