Little while ago I got into a Battletech kick so purchased a bunch of models. All metal. Decided that this time (unlike when I was 10) that I was going to pin them. Unlike a plastic model where I made the pin "straight", meaning that I drilled straight into the arm and straight into the body, I decided to try a new method for the metal. For the arm I did an angle up (looked like this: \) and on the body I did an angle down (looked like this:\). That way, because gravity is pulling the arm down, it's pulling it constantly down onto the pin and constantly pushing the pin down in the body cavity. Has worked well for me. Did some playing with them, painting, and even a packing and move, and no broken pieces. Just my two cents and an alternate way of doing it.