Originally Posted by Bikedued

A carefully applied vise grip wrench will pull a Helicomatic cassette without too much damage. They're more like a lock ring, so usually not as tight as a freewheel. Turn the wheel horizontal with the gears down, and spin the cogs backwards. That will usually back them off after a few tries. I feel your pain, I am slowly swapping out wheels on my helico bikes.,,,,BD