Quote Originally Posted by RobinC View Post
Stuart
O.1mm is only 4 thou (0.004 ins) in old money, the difference in the pellets 4.50 to 4.49 is 0.01 mm which is half a thou-ish (0.0005 ins). When I did my apprenticeship I was told that a good engineer can file to a thou, half a thou is not a difficult tolerance for a good machine. The difference of batches is only apparant when the dies have worn, dies are expensive, so they are then downgraded to a different grade, so a Geco die may have started life as an R10 die.
Oops, decimal point fail