One thing to think about (and this advice comes more from Ron Lake than from me): When pinning (and peening) fragile material (like MOP), use very soft pin material. He uses gold pins, I think. They spread faster, meaning you use very light hammer blows to spread them, lessening the chance of a fracture. Not sure about this, but it makes sense. I've never used gold for anything other than a wedding band, and I didn't make it.