+1 to the advice above, you don't need much to pin, maybe 1/32-1/16, even 1/16" is too much for the one's I do. Be gentle with the taps, never hit straight down, and keep hitting all around the edge in a circular motion, after that, it's just practice. Also, when you cut the rod with the flush cutters, cut it a little over 1/16" and use a file(any file will do) and file it down to the height you want. That will make sure you start with a completely flat surface.