My first choice of improvised tool didn't work well, my thumb. In the end I used the rear end of a plastic tire lever and it was fine. I tightened it more than I knew was necessary to see how that felt, then loosened and freed the arm and did it again the proper way. I checked the feel and then checked for any play and everything spins freely with no play. Since it is a plastic cap you can't tighten it too much anyway. I don't understand why a knurled edge isn't just put on it so you can do it by hand. I already had the tool in my cart but didn't need it anyway. I also improvised the bearing press for the BB bearings, a long bolt, a few large washers and a nut to tighten. That also worked fine.