Drill bits or pin gauges, check every one you use with a micrometer to see what size it really is, not what it's supposed to be.
I also suspect that some import pieces are the closest metric size, rather than the correct inch size, based on some of the variations in measurements I've found.
This.
but remember one thing. a "xxx" size drill or pin will NOT fit in the same identical size "xxx" hole. that requires a press fit.the pin or drill MUST be a couple of tenths undersize to fit the hole. just machining 101. also, watch the edge of the pins when getting close to your hole size determination, as it is easy to get the sharp radius of the pin end to cause a gouge if started crooked in the hole being measured.
