OP

Quoted from BlackCatBone:

Thanks for all the helpful information. I did the following, as suggested by group wisdom: I cut off the old rebound rubber with a box knife. It came off easily. (I saved the rebound rubber in my toolkit for future use when I need rubber mallet, will just tap on the rubber with a small hammer.) I put the new rebound (I get tired of typing rubber and shaft in every other sentence!) in our sink and ran the hottest water available over it for one minute. I washed my hands with bar soap but didn't rinse, I just pushed the suds into the rebound's hole. I pushed the rebound onto the shaft. My hands were so slick I had a hard time getting a grip, but it worked well after a short struggle. And what a difference! The old rebound rubber must have been 1965 original - it absorbed about 50% of the ball's energy on initial contact. The new rebound acts like real rubber, I'm amazed at the difference such a small change makes in game play.