Ach...
Stupid me.
There it is in the instructions...

Seems my caliper ID prongs(?) Are not so precise on a curved surface...
Below a certain ID the offset of the two blades(?), prongs(?) seem to interfere...

My old vernier calipers seem to do a better job on ID measurements...even if I use the digital caliper OD prongs on the vernier since it is so hard to see those little increments....

Thanks all

-OMotS


"If memory serves fails me..."
Quote: ( unnamed) "been prtty deep in the cooler todaay "

Television and radio are most effective when people question little and think even less.