A lot of us who restore and make knives and razors make our own pins for said items. There are a couple hints for making them work better. 1. Make sure the striking face on your hammer is highly polished. It makes the brass (or silver, or whatever you're using) spread smoother and more evenly. 2. Don't stick too much pin out of the washer. I sorta eyball it, but probably not more than 1/64 of an inch should be sticking out past the area you're trying to mushroom the brass head to. Having too much sticking out virtually guarantees bad results, as the head will only mushroom so much without splitting (looks bad) and increases the chance you'll bend the pivot pin (is bad):angry021 3. Don't hit too hard. Hundreds of little taps gets you much better results than a few heavy ones.
Excellent tip... I also anneal the pin material. Heat it red hot with one of those tiny torches, even a torch lighter, and let it cool in the air. The pin will mushroom much easier. You do have to be conscious of the fact that very light taps are needed to prevent bending the pin between the scales within the blade pivot hole.
If the hole in the shank of the razor is too big for the pin material ,don`t forget to to sleeve the hole it helps to reduce the tendency of the pin to bend particularly after it has been annealed Kind regards peter
