Mark Wells wrote:

I put a 2" plane blade on the left side of the jig. Then I tightened
the left nut and made the right nut match. In that case, the right
side of the blade (as viewed from the jig) was slightly up off the
glass. As I tightened that nut tighter and tighter, it got worse. Ah
ha!

Then I switched the blade over to the right side of the jig. I did the
same experiment in reverse. Unexpectedly, the right side of the blade
still didn't touch. I repeated both experiments a couple of times and
got the same results. Maybe the blade is warped? They said in the
instructions to look out for that.

Mark,
When you switched the blade to the right side and tightened up, did
maybe one of the legs come up off the glass, rather than the blade. I
found this to happen, that the blade was still sitting flat, but the
holder had deformed and one of the legs was now off the table and you
could rock the entire blade/holder.

Then I switched to a 1" chisel. No matter how hard I tried, I couldn't
make a blade corner come up off the glass.

That's odd. I found that the narrower the blade, the easier it was for
me to get the blade/holder to deform. However, because the blade was
narrower, it was harder to see: the absolute amount that the blade
corner lifted up off the table was less. (am I explaining that
clearly?)

Larry