So, up to now I've only used 1/8 pins, with no problem. I did a handle today with larger pins and ran into a little issue. As I was grinding them down on an 80 grit belt, they got hot fast. The epoxy within the mosaics must have loosened, and the smaller silver pins within the larger brass tube actually pushed out. I had to stop and let the knife cool several times to finally get them flush.
Question is, what am I doing wrong, and have I messed up the integrity of the mosaics? The finished product looks fine.