After 2 years of no luck and making due, I decided enough is enough. I have been reasonably impressed with the Shars' stuff I've bought so far and their vise looked a little more finished in the pictures than most of the other clones. They actually publish specs -- basically the same +/- 0.0005" tolerances I've seen for the D40 -- and they offer a lifetime warranty. So I bit the bullet and it arrived the other day.
It came with an inspection record, showing the claimed dimensions:
Tolerance Actual
Bed height 2.25" +/- 0.0005" +0.0002"
Parallelism bed to base 0.0005" 0.0002"
Perpendicularity fixed jaw to bed 0.0005" 0.0003"
Parallelism fixed jaw to keyway +/- 0.0005" +0.0001"
As near as I could tell, those are accurate, but we're really pushing the limit of what I have the capability of measuring. My metric Mitutoyu DTI is graduated in .01mm increments (almost 0.0004").
The 1/2" keys don't fit my 12mm table slots, but that's not really Shars' fault and it was short work to make some custom keys 1/2" on one side and 12mm on the other. After 2 years, I have mastered the skill of making a rectangle.
The real disappointment was the dang movable jaw lifted ever so slightly on the final clamp. Not much, but enough to loosen the parallel under a 123 block clamped centre of the jaws. About 0.0002" to the best of my ability to measure. A light tap with a hammer when half-tightened would deal with it. But it shouldn't be lifting, dammit!
So I took it apart. And this is what I found:
So I cleaned off the layer of paint and then polished the surface with a diamond hone just to be thorough:
