I've been using a punch press to punch out small discs (~0.25" dia.) out of 0.035"-thick 260 brass. Because they're round, the angular alignment of the punch and die hasn't mattered. Now, though, I need to make some parts about the same size, but with some features where the alignment is critical. Books on die design abound but I see very little information about designing holding fixtures for die sets that incorporate features for adjusting the positional and angular alignment. Can anybody here point to books or other resources that discuss best practices for designing die holders?