Guys, I have had a half dozen bikes with cotters and although I do not prefer them, they can be very reliable. There is no problem with tapping them in and tightening the nut - provided the cotter has not been damaged like the photo shows. It will not generally do any harm to the BB. With my Raleigh, the original cotters were made of better steel than the replacements, so the replacements were not as reliable. If the cotter has just slight deformation, you can file it smooth and get many more miles from it. I think that buying a press is overkill for what is a very simple job. Realistically you could tap them with the heel of your shoe or a piece of wood.