is one of the most difficult properties to check on dies and die
inserts. A high gloss finish in itself is not enough. Just looking
down a die to see how shiny it is does not constitute a full inspection
of the finish. With a poorly polished die all efforts by the header
operator are minimized.
examination by a trained die maker or inspector of a cast of the
die in question will reveal the level of polish. Any blemishes
on the body or angle, or back taper of the body will result in poor
straightness of the die can be checked with a dial bore gage. This
will indicate if there is any transition in the diameter of the
part being checked.