I have re-pinned about 6 razors now and it seems like everyone of them is off center. I have read the wiki and watched quite a few videos on how to re-pin but I still must be doing something wrong! Should I pin with the blade open or closed? I read somewhere that you should only hit the rod as hard as you would your own thumbnail, is this correct? I use a 4 oz. hammer for reference. Any advice would be helpful. Thank you