Went to install the sleeve today on the rear crank flange... everything went well until I had it in place and went to cut that "flange" piece off.

First off, is it necessary to cut it off, or can I just leave it? It was a real pain in the arse to try and cut that flange to the point of the pre-cut line to pry it away. Once I was able to start prying the flange away, it left the edges kinda warped in some places, even though I was careful to try and avoid that. And I also ended up scratching the sleeve surface a bit when removing that piece. <img src="/forums/images/graemlins/angry.gif" alt="" /> $%^$&^*%$! I'm not having a good evening.

Anyway, I removed the sleeve and will try and get another tomorrow.
Any good pointers here would be well-appreciated.