"Pete C." fired this volley in news:4dfa2a54$0
:


I think that could introduce errors if the vice is not solidly locked
closed/down. The vise way surfaces with the vice open are probably
better since those are the surfaces your part or parallels supporting
your part reference off of generally.


I think that could introduce some errors beyond that.

Unless you're _positive_, Ig, that the plate itself has been ground flat
to within tenths, end-to-end, you have no way of telling if one end is
high, or there are bellies or waves in it.

You need to tram to the surface of the bed, which at least once was
ground to precision.

LLoyd