Transmission Shift Fork Pins

[Dave1931Pickup]

Hi Everyone, What is a good method for backing up the head of the shifting fork pins for upsetting the hollow head. So far I have tried various chisels, screwdrivers and chunks of steel only to find that I need six hands and more patience. Also after they are upset it appears that they would still be loose. Is that right. I've heard a few people say to use roll pins, but I want to do it the way Henry did it.
Thanks for your help, Dave