@david pierce wrote:
The sizes you need depend on the hole diameters you need to measure. For watches this means small sizes. Most of the watch pivots I measured are around .004 inches or .1mm. The sets start at .o1 inches so you will have to purchase or make the smaller sizes. The reason for the minus and plus sizes is the measurement process is done with with the GO/NO GO technique. If the small gauge goes through the hole and the large size does not, the diameter of the hole lies between the two gauge sizes. This means that in order to get the proper use from the gauges, both the minus and plus sizes are needed.
ENCO has a set starting at .006 inches min. to .06 max in both plus and minus. Unfortunately, they’re a bit higher than the imports. However, I guess I’ll just have to cough it up if I want to have an adequate set of tools to approach the sizes that you mention.
As usual, thanks for the information!