You have to "notch" the bottom of the cylinder wall/sleeves. Use a die grinder and do NOT use something that would cut (ie. cutting wheel, hax saw - personally never heard of someone using even a hack saw but who knows, etc.) to "notch" it.

To do it "right" you're going to have to put together the rotating assembly, so it will take time. It's good to save money, though, sometimes something needs to give for a time consuming project such as this.