I fit the alignment pins very tightly and about 10 times as deep as other moldmakers. This to insure extreme long life on roundness. It makes it mandatory that the pins be lubricated with the mold lube supplied with your mold, as often as necessary to keep the blocks closing completely.
If you tend to that matter, diameter should not vary enough that you can measure it with a micrometer, from the time you get the mold warmed up well untill you quit casting, reguardless of the alloy you are using.
