03-06-2012, 07:34 PM
(03-06-2012, 05:12 PM)stevec Wrote: Arvid, I hope your questions have been answered, Sometimes the jocularity obscures the legitimacy.
You've had one reply that "One side will be ground flat and the other is usually kind of rough."
Is your plate like so? (I doubt you would have asked the question if it were blatantly obvious).
The other point of parallelism you've answered yourself and I agree.
So, to reiterate, because I'm curious, are some surface plates ground to the same flatness and surface precision on both sides?
The reason for the question was to see what "was normal". I just looked at mine and it is like Ed's ... rough on one side. But then it is a Grade B import. But no one has suggested that if I had purchased a "xxxx" then both side would have be ground flat and parallel so maybe they do not exist outside of NASA.
Which makes me wonder about the sides? They are ground. I guess I will have to test it to determine if they are flat and parallel.
And for those wondering why ... I have an 8 inch precision level and 11 inches between the two items I want level. The granite plate is the closest thing that I have that is flat and ridgid enough to span the gap so I can then then use the precision level to make it level.
But my next plan of action is to level the granite plate with the precision level, then use that as a reference to see how far off my aluminum levels are, adjust them so they are accurate enough to use across the gap and then call it done. The aluminum levels pass the "flip it around test" but I am interested in the last little bit of accuracy.
And the whole thing is more of a mental exercise in the possibilities for precision than a requirement of the task ... and curiosity about what normal was.